So, for this long, long, long back people try to put all these probability theory in a very, very systematic manner, so that all of us are on the same page when we are talking about these term things and also they lead to kind of intuitive properties that we want them to satisfy. So, that is given by something called some one called like Kolmogorov you might have heard this name. So, he built this all very systematically by introducing this notion of what we call as probability space and this is, so to do this he introduce a triplet called denoted as omega script f and p. Omega is same as earlier, it is the event space, sorry sample space, so what is the difference between sample space, event space, did we say that the same right, like I mean this is a collection of, so okay, so that, so what is, so I just by mistakenly said sample space, sorry event space, but I have only introduced this as sample space, so this what does the sample space constraints, it contains only possible outcomes, event space could be collection of events and that is where this f come to picture, so now it is not necessary that every subset of a sample space is an event of interest to you. Okay, I mean for example, let us say two guys, they are making some decision, let us say just making s and no decision, one guy says s no or other guy also has to say s and no and these guys are just like dead opposite guys, I mean they will never say the same thing. Then you already know that s s and no, no option is out of the picture, right, you do not want to consider that event at all, so and in that your events of interest are only now restricted, it is not that all possible subsets of your sample space okay, so that is there, now this will define what is that possible set of events that you are interested in and now once you restrict yourself to possible set of events, now on that you want to assign the probability that that outcome is going to happen and that is what the third term is going to define, okay, particular event that is coming from this event space, I am going to make it more precise, so let now this is your sample space, so this always happens, right, like do you see why this should be done, like why this, I will not always consider all possible subsets of sample space as event, why I will be only taking only some of the events, so you can imagine, right, like when you are going to do an experiment based whatever the outcome and when you are going to do this experiment, let us say two or three of you are going to do this or whatever you are individually doing, you know that some outcomes are not possible, even though that outcome is there in the sample space but when you are looking at that particular event that may not happen, so can anybody think of a example that you have seen in your daily life where this can arise, I do not know, let us take one hypothetical example like let us say you are reaching airport and your friend reaching airport and let us say you are another close relative reaching airport, what are the possibilities all three of you reach, none of you reach, one of them reach, two of them reach, like that, right, there are so many possibilities but you know that one guy is already in the airport, right, so that guy is never going to be, so that guy is already in the airport, right, that possibility that that guy is not airport, all of this option is already eliminated. So, there are always such among all the possibilities such combinations can be eliminated, right, so that is why you want to restrict yourself to some events which are not which is not necessarily always a subset of your omega, yeah, maybe you can think of better real life example, it is not on top of my mind now, okay. So, fine and this one we are going to call it as event space, this is basically set of subsets of, we are going to call it as event space and this last term we are going to call it as probability function or probability measure, okay. Now, let us see, so the script of here is basically collection of events, right, this is an event space. Now, as I said it could contain either all set of subsets of, all subsets of your sample space or it could contain only some subsets of your sample space, okay, but how that should be like if I want to do a consistent modeling, how this f event space should be, so for that we are going to make some axioms that is going to say how this f is supposed to be, okay, so for that we are going to say something like, we are going to call event space, okay, event space. So, let me write the properties for this and let us then discuss whether they are natural or you expect this thing to be at least as a necessary to happen. So, we are going to say some event space f to be sigma algebra if it satisfies the following, first thing I want is this omega to be included in my event space that is entire collection of my outcomes should be included in f and then if some event if belongs to f, then a complement belongs to f, f is not, no, f is a collection of subsets of omega, okay, so this is the omega, that means f is a set of sets, you understand this, that is what I said, right, set of subsets of omega, yeah, you can think of power set that is the largest possible event space you can get, right. So, okay, before I write this maybe an example is good here, okay, let us take our trivial thing omega equals to h and t, what could be an event space, it could be simply h, that is it, only an element or f could be h and t itself like it has the both elements or maybe just has f equals to t or it could be null set, anything is possible, right, that is what I am saying, I am going to focus on certain sigma algebras, I want, now I am telling you what are the properties of that event space, okay, what is the properties, I mean when I call it a sigma algebra, so first thing I am saying omega, omega is itself a subset of itself, right, omega is a subset of omega, so it can be a possible candidate in f, so I am saying, okay, when I say sigma algebra that omega belongs to f, if any, if suppose let us say some subset of omega, let us call it a belongs to f, its complement also belongs to f, then, okay, so in this case it makes more sense to write them as, so okay, fine, so this should be like this is one, this is just one and maybe this is one or other possibility here just to make it more clear is, it could be like h and t and just h, all of you get this, so I mean, so earlier this is what now the distinction, when I say it in a flower bracket, this itself is a set and here this is a set, this is a set and now this is f is a collection of these two sets, so a is such a subset, right, because this is a one element in f, one element in f means this is one subset of omega, is that clear, yeah, set you call a b or b a, how does it matter, it is just a collection of sets, yeah, you just say 5 people, you do not say who is who, okay, that is all right, order, I mean if you want to say order, you need to define what is order, right, when you say order, okay, this guy is greater than this, that guy is greater than this, order, we are not getting into, we are just writing, this is one set, this is one set and the third point we want is, okay, so we want is if a and b belongs to this f, their union also belongs to f and as an extension to this, also if a1, a2, 0, sequence of then, so okay, so I am saying if I have a collection of subsets, which I am going to call event space and I am going to call that event space, particular event space to be sigma algebra, if the following holds, so first thing is omega belongs to f, so do you think this is natural, I should include omega to be in event space, so simple question is okay, let anything happen, that means enter omega, right, so let omega be in f, okay and now if you say some event happens, there should be some meaning to that event not happening also, right, so that is why if a belongs to a, a complement belongs to it, if you say a can happen, b can happen, then you should be able to answer whether both can happen and that is what a union, b that has to be there in scripted and also you like that instead of just 2 or like finite number of unions to be in f, you can ask, okay if I have a sequence of events from my script f, all this a1, a2, they belong to f, then I want their union to be also in script f, so this is all right, when I am conducting trying to model something, some random thing and if I want to define the set of outcomes, in the set of outcomes, I would like the outcome omega to be included, if a belongs its complement to be included and this unions should also be included, okay let us take again, let us go back to our H and T, right, these are just outcomes, I said these are all possible subsets, right, these are collection of subsets which I called them, what is the best possible, what is the largest subset of these sets, number of, what is the largest number of subsets from the sets I can get, 4, right, what are those, H, T, H, T and null set, that is like a power set, right, but I had here considered only some subsets here, that is what you want to know like that is, so okay fine, let me write it, if there is one possible is f could be H, T, H, T and null set, these are the only possible subset of omega, right, I cannot add anything more here, this is the largest, but why should I look for the largest, I could also look for the smaller than this, in this case this could be one possibility, this could be one possibility, this could be, but all of this need not be sigma algebra, okay, now let us say, if I am going to define f to be like this for this omega, is this the sigma algebra, right, because now just, best thing is just go and apply plainly these axioms, so this is why we are going to call them as axioms, but because these are fundamental things which you need to hold, and these are definitions, when we are going to talk something sigma algebra, the only thing that is common to both of us is these definitions, okay, now let us take another H and T, if this is sigma algebra, so right away the first condition is violated, right, yeah, meaning of sigma algebra is implicit definition, I am telling this is what then you are asking what is that, so okay, telling it in other ways, sigma algebra is some sensible set of events, I want such that they satisfy some property, okay, that means reasonable sense, that is what I said, right, it is something which should include all possible outcomes as one possibility, if something happens naturally the question you are going to ask is what if that event does not happen, so both happening and not happening should be there, and the second condition is what that, so I am going to say, okay, that happened, this happened, can both happen, this is what you guys are always asking, right, I mean, yeah, if I did that course, can I do this course, if I drop that course, can I do this, if I want to shift it, can this be possible, I mean all permutation combination can happen, but as we all most of the time reject that, right, they are only going to take some possibilities, and this is what those some possibilities we are going to define, okay, so this is not a sigma algebra because it does not satisfy the definition, suppose I take a simple thing in this, so what is the simple thing, this is, is this a sigma algebra, yes, quickly apply for all the three, all the three condition, fine, right, it satisfies, omega is anyway there, if a, suppose if I take this to be the a, a complement is phi that already belongs, if I take a to be phi, phi complement is omega, so we are going to talk complement with respect to the sample space, so complementation is happening with respect to the sample space, so when I say omega equals to 1, 2, 3, 4, 5, 6, and let us say a equals to 1, 2, what is a complement, 3, 4, 5, 6, suppose now I redefine my omega to be just 1, 2, 3, 4, 5, if I take a to be 1, 2, what is the complement, so just this guy, so always my complementation is with respect to what omega I am talking about, okay, if my omega changes, my complement can also possibly change, and yeah that is the exact thing, my complementation is with respect to my event space, okay, these are like, this is a very toy model, right, we are not getting that more leg space here to construct a nice event spaces which are not sigma algebra, let us take bit the dive problem, so in this let me construct a simple thing, so one possible I am going to take is, so first I will going to include omega that entire thing, I will take 1, 2, 5 like this, and let us say I will ask you, give me one element here that will make this f sigma algebra, we just want to take the complement of 1, 2 to make it any other elements required, suppose I have added one more thing, now tell me how many terms I should include in this, so that it becomes sigma algebra, what are those, so okay fine, so now I have these elements this, so now tell me what all the things I should include in this, complements of this, okay, 3, 4, 5, 6, tell me one by one, so first go systematically, right, first thing is their union should be there, so 1, 2, 3, and then it is complement, okay, so I have the complement of this, now what is this, I have to bring a complement for that, right, what is that value, enough or I need more, more what, omega, right, so the union of this should be there, right, it is already there, okay, we are done, done, so no more addition is required, right, so fine, so what we are doing is we are just sticking to the definition of this, so that we are, we call it as sigma algebra, okay fine, what we just said is, in this condition, in this axioms, basic axioms, you will see that these are the bare minimum things I need in my event space, so in this I did not say that if a and b belongs to script f, a intersection b belongs to script f, do I need to explicitly say in this or that is implied, so a, b belongs to script f, I know that their union belongs to script f, suppose f is a sigma algebra, does a intersection b belongs to script f, why, okay, tell me a union b belongs to f, this implies then b complement and belongs to f, so does this imply, does this imply a intersection b belongs to f, okay, start wherever you want, what do you want to start with, fine, then I want to reach here, you want to take the complement, okay, I mean union, then you take, so if this belongs, I know that this complement has to belong to this, then it is, then once I have this, I also know that a complement union b complement belongs to f and you can see that this is nothing but a intersection b and once you have this, similarly you can go and extend, if you have a sequence of elements in f such that their union belongs to f, you can show that their intersection do also belong to f, same set of arguments, okay, so make sure that you work out that, okay, okay, so last thing, so we are going to now revisit what I have already defined p function, now I am going to make, define this, so p of, now this p is defined on f, see the way we have defined this triplet, omega is a sample space, f comes from this sample space and now this p is defined on this event space, once you give me this event space, I do not care what is your sample space, to define my p, so we have already written this, let me rewrite p of a is equals to 0 for all, it equals to f, okay, let us see now what is the implication of? Normal probability and probability is measured on f, so there is not any difference, we are just making this the same whatever we have defined earlier, now we are trying to define it on my event space, right, earlier I have just defined it on any possible event, right, you just take an event, now I am saying that fine, I do not need to define on any possible event, I am going to take this bit more systematically for a given random experiment, I am going to represent it using these 3, omega, script f and p, omega is out, outcome is the sample space and script s is possibly the events of my interest and on that this probability is now defined. And now it is the same thing, earlier a was any event, now I am making it more precise to make this replacement clear that this probability is now defined on the elements of script f, okay. Now, from this, is it true if p is a probability function, we are not going to use this word measure, measure is for a bit more abstract, more general things, I mean in the space we are looking at let us simply keep calling it probability function or a probability function defined in this fashion, is it true that probability of a, is a probability function, it is defined, this probability function is defined on an f, right, f includes null set, so I should know what is the value this probability gives on the null set, what is this value is going to be, can you show this or if you have to show this what should be the argument, okay, let us take in this case I know a, let us take a to be omega itself, omega belongs to f, right and by this if omega belongs to script f, I know omega complement also belong to script f, so omega is equals to omega union, omega complement, right and in the space of omega what is omega complement, it is a null set by definition and this omega null set this joint, yes, right, like there is nothing about this, now what is this I can, now how can I conclude, why is that because of my third part, so this concludes that my p of e is equals to 0, so do you expect p of a plus p of any thing to be 1, so can we, is that, is this necessary that I have to include this in as a fourth condition or this is be implied from these three conditions, how, so what is omega, right and is a and a complement are mutually exclusive, so then we are done, right and we know this guy is 1 by definition and now suppose let us say a, b belong to script f and let us say a is a subset of b, so do you expect the probability p to give more value to this event or this event, more value, you expect it to give more value to b, right that is, so do you think I should include this in this condition, so this is natural, right if we want this, if one event has more elements, this probability of likelihood is more, right, should I include this here or, so this is a requirement, right, I like this to be there, like I want p to satisfy this, is this implied by this condition or I have to include this, why, how, construct, so what can one of you say what could be the arguments to show this? b minus a intersection b is another set, b minus a intersection b, b minus a intersection b, ok I will just write whatever you want to say, b minus a intersection b, what is this, let us to make our life simple, let us take this to be a set, b bigger one and let us take a to be something contained in it, yeah, so I mean there could be many possibilities, can you think come in, I want you to give the full thing, ok fine let us try to construct, so the thing we know when you want to apply this, I want to like somehow bring in mutually exclusive sets and complement, so let us see, let us see if I, I know that this set a and whatever that in this, that disjoint, right, how can I represent the guy in this b minus a, ok you tell, is this correct, what is this b intersection a complement will give me, the shaded area only, right. Now, how can I write probability of b, how can I write b, a union, right, now let us call this c, some set, right, does c belong to f, a y, does c belong to f, why? There are two things that belong to f. So, I assume a belongs to f, so is a complement belongs to f, I assume b belongs to f, so both of this belong to f, so this intersection belong to f, I said intersection of two element belong to f also belong to f, right, so this c belongs to f. So now, I have this, I am going to just write it, I have this b written as a union c, I have argued that both are disjoint and both belong to f and on both of this I know p is defined. Now, what is this, I know p of b is equals to p of a plus p of c, why this? My third property, now with this I am done, now I go back to this and I know that p of c has to be non-negative, right, like it has to be greater than or 0, then it must be the case that pb is greater than or equals to p, so like this you can, these are like, that is why like these are called axioms, these are very, very elementary conditions I required, they are going to imply lot of things. So, they imply many things which I am going to just write and I expect you to work them out and some of them will be also in your assignment, so these are three, maybe like fourth is, so earlier I said that I expect this property to hold intually, but you can show that if these three conditions holds, this is indeed true for any a, b belong to script f. And you can generalize this by taking, yeah, other things we have derived and you can derive many more properties which I will skip. So, some of these more properties that you can derive out of these axioms, you will see in the tutorial session, yeah, okay, the last one. You can also visualize all this through this Venn diagram, right, I mean you should, whenever you, it is possible just draw Venn diagram that will help you to understand all these relations instead of memorizing the Venn diagram should help. Okay, so let us stop here.


In addressing the fifth section, we have to return to the powers and authorities that belong to the people in whose name this constitutional agreement is being signed. No citizen has the power to determine who will be the representative for her neighbor. That authority is personal. They cannot give the gathered Congress the power to challenge the authority of any elected representative. There simply is no authority to interfere with or to prevent the election of representatives. Proclaiming Congress to be the judge of member elections does not let the body of Congress establish and enforce its internal rules as to its own membership. Congress cannot refuse the will of the people who elect a representative, but they do not have to accept the representative as an active member of Congress. This section recognizes the right of the members to look at the details of election and to judge whether any elected person is fairly elected and has met the minimum requirements for fulfillment of the congressional office to which he or she was elected. Beyond this, there is the power to regulate the behavior of the members of Congress when acting as a member of the body. This is, by writing, even open to assessment of punishment. In the common law, punishment is the assessment of a negative consequence to some act. Punishment by the common law was an extraordinary power. No person could legally punish his neighbor. Punishment was reserved for the sovereign authority and limited to established crimes and misdemeanors, or to exercise the right of sovereign to rule. It was like the power of parents over a young child enforcing parental rules on pain of active parental response. The effect of this provision is to set the body of Congress into sovereign authority over its members, but with the limited purpose of seeing to its operation as a public body serving a public purpose. A specific note, this does not give Congress any additional powers or authorities when dealing with the people who elected that representative. It assumes that discordant behavior by any elected member of Congress is misrepresentative. Punishment goes to the member instead of reflecting on the people who are represented. The Journal of Proceedings is a requirement for management of the legislative business of Congress. Writing it into this provision is clearly beyond simple management, especially when the provision allows exemption of items from the record. What this justifies is a separation of the journal into two volumes. The one to be public containing the records of operation that any citizen may see. The other is secured and is a record of the actions that are not to be published. It implies the publication of the one volume. It does not address what the Congress is to do with the other. The final provision addresses the intentional coordination of the two houses of Congress. It addresses simultaneous meetings, implying intent that they work in coordination and fulfilling the purposes set forth in this constitutional agreement. The lead paragraph in Section 6 arranges for the members of Congress to be government employees. They are to be paid from the common treasury. This has a secondary common law impact as it deals with the laws that apply to employment. One immediate challenge is that these representatives are not employed to represent the United States as a whole, but to represent the people who are the base for their election. Payment from the U.S. Treasury is not meant to interrupt this and must accordingly address citizen owner's rights in the Treasury. The government gaining funds in the Treasury is not meant to interfere with responsibility to represent the people. It speaks to the need to see funds within the Treasury as belonging to the people. Funds collected from those in representatives' area of representation belong most directly to the citizens being represented. Other funds, as those collected from regulating international commerce, are shared in ownership with all the citizens of the United States. Simply dumping funds into an omnibus account is probably improper and is certainly poor management. The effect is to assure that the members of Congress are to be paid out of a representational portion of the funds held in the Treasury for that representative's territory. Separate accounting to the people represented should be appropriate. The obvious intent of a congressman's immunity from common arrest is to assure that the representative's unfettered ability to represent is maintained and to act without fear of personal reprisals when engaged in the people's business. There is, after all, provision in the previous section for self-regulation of Congress as a body with ability to contain disruptive or improper behavior by such rules and actions as Congress may choose to put into effect. The intent has proven to be unrealized due to the large amount of legislative business being completed by this body of hundreds of people. They do not have time and opportunity to self-regulate through their internal corporate actions. As a matter of general practice, they simply allow members to commit slander in hopes that the public will not support their representative in engaging in such published criminal acts. Even where the slander is intended to damage someone's ability to pursue their chosen profession, it has gone unpunished. Most recently it has even been used to slander for political benefit, intentionally interfering with the representation of candidates for congressional or other elected offices. This provision has been openly and widely abused without restraint. But any correction is a matter for Congress, and accordingly not for lesser government bodies or authorities to interfere. Where we the people have authority to interfere, we currently have a lack of good and recognized process for action, even if we come together to address matters of concern. The second paragraph also addresses avoidance of representative bias, putting a specific ban on actions and relations that would divide their interest and loyalties by secondary employment. They are, for the time they are in office, to be focused on the people's business. This provision does not require direct member action. Again, the first focus in Article 7 is on finance, on the importance of handling the people's public money. It is also indicative of the people's intent that the bill's raised revenue must start in the House of Congress that is most representative of the people. This government's gathering of funds is the people's business. This further emphasizes that funds in the Treasury are also the people's business. The public is seen as having a direct and abiding interest in the public money residing in the U.S. Treasury. The following paragraphs specify the general process that is to be used for passing laws. It is significant that it includes the President as a check on the authority of Congress, even as it does allow a supermajority in both houses to see to the representative will if the President is not disposed to support congressional action. Article 8 enumerates certain powers that will belong to Congress. It accordingly sets effective responsibility upon Congress to exercise these powers on behalf of the people of the United States, seeing to the purposes given. It is noteworthy that a large percentage of these go to financial operation of government. This is a major matter of interest in the people's delegation of powers to the government formed under this founding document. There are specific provisions addressing the militia, the people of the nation as volunteers for military direction. There is specific authority to call these bodies to national purpose. There is not exclusive power as it is of a volunteer force, people by sovereign citizens. The state also has potential for military efforts. There is authorization to create federal enclaves, where federal law will be the sole legislative authority. It is significant that, except for the seat of government, all such lands must be approved by the states, the territorial representative bodies, before an enclave can be legally established. Inheritanness is the right of the state as the people's territorial authority to withdraw their approval, reclaiming their territorial rights to represent those who are within their borders. Territorial authority other than the seat of government rests first in the states and then in the constitutional government arranged in this agreement. The ending of this list with a catch-all provision indicates that the list is to be inclusive, not exclusive. There are other powers that will belong to the Congress, even though not included in the list. Where section 8 addresses things Congress was to do, section 9 addresses things that Congress is specifically not to do. It bans many historical interferences with citizen activities that are to be recognized as citizen rights and privileges. It includes some privileges recognized in the state governments. It specifically directs that Congress not favor any state over any other in matters of commerce. It also strengthens the ability of people to manage their government by assuring published account of receipts and expenditures. This has proven to be limited in effect as secrecy is also specifically permitted. And as involved noting the expenditures and receipts, but not requiring a specific statement of the particulars for otherwise secured transactions. There is good reason to believe that this has allowed and supported some public abuses. Section 10 deals with recognizing those traditional trappings of sovereign government that are reserved to the Congress. In writing of this provision, it is somewhat awkward as it is written in a negative, addressing powers and authorities as being forbidden to the states. While this is somewhat in accord with the signing of the document by colonial state representatives, it should be read as this document setting limits upon state governments as denial of state sovereignty. This document, however, especially Article 1, addresses the creation of central Congress and not definitive as to other bodies. It suffices to grant exclusive jurisdiction to the Congress on matters covered. The states are not to be recognized by those in Congress to be separate sovereign governments. Neither does it subordinate the state government to a new government, but merely limits their ability to act as sovereigns where Congress is given jurisdiction. It should appear that the states by their acceptance also accept the indicated divisions of authorities. The very act of writing of this constitutional article sets duties upon Congress. It sets specific limitations on its authority to act. The larger agreement among we the people as to what they grant, government, contains its own set of limits based on the larger purpose of self-governance. The U.S. government is not able to act as a sovereign over the citizens of the United States but to represent their interests in accord with the written agreement and within its stated purposes. The first purpose of Congress is to pass laws delivering services to the people. The second is to perform internal management of the operation of government on behalf of the people. It is also provided with a list of specific duties to address through the operation of the Congress. To draw together, it is an act in coordination with the President in the legislative efforts to support an executive arm of government through passage of laws. This is not a matter of checks and balances so much as direction to act in coordination with other elements of government and assuring the purposes of government as set forth in the preamble.


Today's lecture is in continuation to the previous one where we looked at the importance of a very useful technique called pulse laser deposition and this has been one of the path breaking event in the area of thin film technology where you can translate most of the studies of bulk materials into thin films and not only to study in lower dimensions but also to bring about lot of device applications into perspective PLD has been a very decisive method and we have looked at some of the constraints how sensitive this process can be and we also tried to understand the dynamics especially the plume dynamics how it affects the growth quality of these materials. Today I am going to concentrate on another equally competing thin film deposition technique which is called pulse electron deposition. The fact that we are replacing the word laser with electron suggests that the source of deposition is going to be different. So instead of using a pulse laser beam we are going to use a pulse electron beam and we can see why PED is more important that way and what are the advantages and disadvantages of PED over PLD. So in this PED deposition which is fairly a new technique compared to PLD we will look at how we can make thin film structures, nano structures and how this can be used for device applications. So let us start with understanding what PED is. Pulse electron deposition is a process in which 100 nanosecond high power electron beam which is approximately of the order of 1000 angstrom at 15 kilo electron old penetrates of about 1 micron deep into the target and as a result there is a rapid evaporation of the target material and this transforms into a plasma. So once it is a plasma it gets deposited on the desired substrate which is actually a non equilibrium extraction of the target material and therefore because of this nature of transporting the ions and the atoms you can ensure a fully stoichiometric composition of the plasma and that way we can make a single crystalline film. There are some issues which act as strength for PED compared to PLD therefore it is better we familiarize why PED stands out in many ways compared to the most established PLD technique. In contrast to other techniques such as conventional electron beam evaporation the main feature of this pulse system is the ability to generate a high power density of 10 power 8 watt per centimeter square at the target surface. So you are actually focusing this highly intense electron beam on the target and as a result thermodynamic properties of the target material such as melting point and specific heat becomes unimportant because you are overcoming all these issues by a high energy pulse and as a result you can evaporate any sort of material that you want. So this is particularly advantageous in the case of complex and multi component materials where you have more than 2 or 3 metals then you do not know how these materials would respond to a pulse laser or to a pulse electron beam you would see they behave in a more friendly way with PED technique. As in the case of PLD, PED provides a unique platform for depositing thin films of complex materials and therefore it is very viable for applications and mass production and as a result this is one of the scalable and cost effective high volume manufacturing process. We will look at several examples and understand where it has a age over PLD. If you recap the previous lecture on PLD you would see that the instrument itself is quite big because you need to bring the laser plume into the vacuum zone and as a result several optics is required and then you also have the big laser system which is going to occupy. So comparatively PED technique is a very very amiable process because even in lesser space you can try to install this system. As you would see here this is all the dimension of a PED and what is important in this deposition technique is the pulse electron source which is called PEPS source and this is the core of the PED technique where the pulse electron beam comes from this but for that the vacuum chamber and all the energetics are nearly the same like a PLD. So what you do you avoid the complex problem of maintaining a gas source for laser and then the cooling systems plus the optics to guide the laser light into the vacuum chamber. All these are avoided by just using a laser electron source. So this is a typical way that you can energize a material by shooting a pulse electron beam and the target is now ablated and it causes this plume and then this plume travels to the substrate. Although the pulse electron beam looks very fancy and simple but to take a closer look these are the elements that are involved. You have a hollow cathode and this is focused on to the vacuum chamber. This is the vacuum chamber and this is your PEPS source. You have this capillary tube which is usually a ceramic and then the hollow cathode here and this is focused on the target. So critically although it is simple but the making of the PEPS source is a tricky stuff which is the most important element of a PED chamber. Now to get a quick look at the cost effectiveness between PLD and PED before you look at the examples of how the PLD and PED grown films look like you can clearly see the standout because it is almost one eighth of the cost that is required. So if you are looking for a one energy source of a PLD you may have to shell out nearly 400K of US dollars whereas PED is just 50K. So therefore you can actually get more than 6 PED chambers for installing one PLD chamber. So cost wise it is very effective and therefore it is very useful for mass production and deposition station. So PED costs just 10% that of PLD. If you quickly want to look at the dynamics where PED is different when PED is in operation you would see a channel tube which is also flashing or illuminating during the process and this is nothing but the ceramic tube which is actually guiding the electron beam and this electron beam actually falls on this target. This is the target which is of a typical 25 mm disc target. So when the PED strikes then you can see this plume is coming out. So this is a typical photograph during the operation process. So the control of this plume and what is happening the composition and the target which is mounted here perpendicular to the plume all this governs the dynamics of PED process and either it can make it more novel or more detrimental to the film that is grown. So this is all we are going to understand in the next few slides as to what are the critical parameters that govern this issue. When we talk about this specification of pulse electron beam source we need to understand the critical advantage is that you have a pulse width of 100 nanoseconds which is comparably different to the pulse width of your PLD process and then the pulse energy range that you have is quite tunable. You can go from 0.1 to 0.8 joules so you can actually vary the strength of your pulse by operating with a different measure of the energy of electron beam. So when you talk about electron beam you are going to operate from 8 kV to 20 kV so you can change 8, 10, 12, 14, 16. So with this the pulse energy also will be affected but the pulse width will remain the same. So you can actually tune this for a variety of substance including biomaterials to ceramics to metallic materials to insulators you can play around with the energy of your electron beam and the pulse energy therefore you can make a judicious choice to bring the right mixture. So these are some of the specific numbers that govern the PEP source and you can also see the beam cross section is pretty sharp which is 10 into 6 into 10 per minus 2 centimetre square so you can really spot on a very small area which means even with a 10 mm target you may be able to do a PED deposition. What sort of materials that we can coat using PED as a thin film? The spectrum is quite large now and you can see starting from a superconductor to a photonic material like zinc oxide to a photonic material again tin oxide or to all these insulators or to polymeric substance to ferroelectric and magnetic substances or metallic substances. You see a wide range of compounds that can be used ITO of course you know is the base material for any photonic applications so if you look at the spectrum of materials that you have you can actually play around with almost any material that is possible through PED and what is the control? You can actually go for at a position rate of 0.1 to 1 angstrom per pulse which is a very good choice so if you want a slow growth you can affect a slow growth process if you want a rapid deposition you can do that. At the optimum distance between the target and the plume of say 6 centimetre you can actually vary the deposition rate considerably. Now the parameters that control the film growth has some numbers in it so when you are actually having a substrate which is your single crystal here and you have mounted this substrate perpendicular to the plasma. Now then energy of the arriving atoms here which is in the end of the plume and the number of arriving atoms which together these are n into e1 they depend on the plasma energy balance and the electron beam intensity which is actually given as J in ampere volt in kilo volt and time in second. So these three parameters govern what set of energy with which the atoms arrive at the substrate and the number of arriving atoms so this is all it takes to control therefore for every given material you need to make sure that you have a proper energy balance because the way you try to have evaporate zinc oxide will be quite different from the way you evaporate nickel for example a metallic material. If you want to ablate aluminum oxide then you need to have a proper energy balance. So depending on the band gap of the target material and the energy balance that you choose you can optimize the plume or the plasma flux. If you look at the electron beam generation which is actually coming from a trigger and you trigger it through a hollow cathode and it is actually coming to the vacuum chamber which is your anode you would see for a 20 k v pulse for example if you provide a channel spark discharge for every pulse you would see the d k will be of this fashion this is for the voltage and then you would see the current going through a minimum then coming down and in this process you would see the pulse width is actually full width of half maxima ranging to 100 nano seconds. So you have a very narrow range where this pulse width is of the order of 100 nano seconds and this is the prime importance for the PD process where you have a electron pulse which has a very very sharp breakdown and the pulse width is as close as 100 nanometer. So with this pulse it is possible to almost bring about many changes when the electron beam is actually hitting on the target surface therefore when such a high energy pulse is actually hitting the target. Now you can look at how the materials get ablated for example the electron range which is actually a factor of v square electron range if you plot as a function of the electron beam energy you can actually keep on varying as you would see the operation are at higher voltages are not actually favored. So anything beyond 14 although it can be done it is recommended that we do not strain the instrument by operating at very high voltages and also you would see that the heavier metals are ablating much better compared to oxygen. So in case of silicon for example the electron range is easily achievable up to 1 micron even with 10 kV whereas for alumina and itrim barium copper you see substantially they are lower. So if you are going for 14 kV it is very easy for you to achieve an electron range of the order of 2 micron for optimum kV of 14 kilo volt. The target heating is actually more dependent on the electron range and if we have a proper calibration for different materials then it is very easy for us to choose depending on the target to the plume distance. With this electron range it is possible for us to determine the target heating because continuously this nanosecond pulse is hitting and this target heating range is nothing but a beam power over electron range. So if you know the beam power and you know the electron range it is possible for you to measure what is the target heating rate. So depending on that if you make a plot you would see that it is not linearly varying rather it is actually going through a maxima. So maximum heating can be achieved at 14 kV which is a very useful information. So instead of struggling at very high voltages if you can optimize for this numbers then it will be more efficient for you to do the application. In other words for this beam power and electron range if at 14 kV you achieve maximum heating then we can try to bring down the other parameters like target substrate distance is closer so that we can work at this efficiency. There is an optimal e beam voltage for PED and that is what we see here. This is another useful guidelines from Neosera group which gives us some idea why PED may much more efficient than PLD. For example if you take a 248 nanometer laser, Krypton fluoride laser and use the PLD you would see very comfortably we can deposit silicon carbide, titanium, strontium titanate, tantalum oxide and silicon nitrate. These are very easily deposited using a PLD instrument whereas when you look at the band gap of some of these materials like yttria or zirconia or magnesium, silica, alumina all these are showing a band gap above 5 and if your XMR laser can generate only 5 electron volt it is impossible for you to ablate with ease this high band gap material. Therefore this is where PED comes into picture. So with PED you can actually deposit any of the insulating compounds or compounds with very high band gap. So that is one of the reason why PED still stands out as a more prolific deposition technique. With this in mind at a distance between the target and the substrate of 5 centimeters you can anticipate typical deposition rates of the order of 1.6 angstrom per pulse if you are going to deposit yttrium barium copper oxide which is a superconductor. If you go for Syria you can easily ablate that calcium, cobaltite, alumina, silica all these insulating materials you can easily ablate with a very high deposition rate. And you can also see that the photonic materials you can update ablate with fair amount of ease and these are the metallic materials although the ablation rate is nearly 10 times lower yet it is possible for you to ablate the metallic materials also. So the type of materials that you have and the electron beam energy that you use with a fixed target to plume distance you can actually achieve this sort of deposition rates. So one should not think that anything and everything operated with PLD will have the same deposition rate. So it varies with the system and how it takes up the electron beam. As you would see here if this is your substrate and this is your gas zone and this is your plasma which is generated at the interface with the target you would see at 100 nanosecond this is where the plasma is and the kinetic energy of your plasma or the ions that are generated is much much higher than one electron old. But as the plasma progresses towards the substrate you would see in one microsecond the kinetic energy is falling down and it is falling down much much lower and then it becomes a thermally activated deposition. So we should understand how the plume propagates and therefore depending on the material it is possible for us to fine tune the system. The flux dynamics is almost similar to PLD as you would see here in the first 100 nanoseconds when the pictures are taken this is your target location and the way the plume propagates this way towards the substrate you can see the plume is actually getting discharged or it decelerates in gas so over a period of the decade time. So at 100 nanosecond is just about to flash and then as you go down to 700 nanoseconds you can see how the plasma decelerates in a particular gaseous environment and you would also see this white region is the region where maximum kinetic energy is there and it is still sustaining at 700 nanoseconds. So with every pulse shot the pulse actually propagates in this fashion from here to here and then it goes and strikes on the substrate to form the thin film. Now I will go to some specific examples show you some thin films and also draw some conclusions on plume dynamics and stoichiometry which might help us understand the dynamics of PED process. Some of the examples are taken from the literature one is from NISTAR and co-workers who have worked on a variety of oxide films and they have made quite a good amount of calibration so I want to touch on few examples from NISTAR's group. This is nice image of the visible emission of hydroxyapatite which is a bone material and you can actually translate this hydroxyapatite into a thin film form not necessarily a bulk form and you can try to look at the strength of this hydroxyapatite films and if we have a way to deposit as a thin film then we can try to do it on variety of substrates. So here is the situation where you have this target is nothing but your hydroxyapatite and then you have the substrate you are ablating using electron beam. Look at the progression of the plume and this is actually a luminescing plume because all the ions in your hydroxyapatite usually calcium phosphorous all these are actually fluorescing and once you trigger the pulse at 0 nanosecond this is how it is but they specially grow with time and that is what you see here over a period of 3500 nanoseconds it has actually specially grown and you can see the zone the temperature zone and how the species are still luminescing over this transient period and during this period we also understand that the heavier particles and the lighter particles they take their share to reach the substrate surface and as a result we can have a knowledge of how complex materials can be grown. The mapping of these flashes gives us idea about the stoichiometry and how the plume dynamics can control the n stoichiometry of the film. This figure gives us the velocity distribution of the species corresponding to the image taken from the previous example of hydroxyapatite as you would see here the velocity distribution ranges from 0 to 3 centimeter which means you have both the high energy particles as well as low energy particles travelling together and the spectrum is quite large and this is the one which really makes the difference between PLD and PED. In PLD typically you would see the spectrum coming like this which means you do not have edge for heavier species to travel and because you have the velocity distribution of the species quite large it makes it more versatile for you to prepare films with less particulates otherwise you will end up with the thin film with lot of particle chunks also coming into picture. Because of this velocity distribution you get a much finer film compared to PLD and I will show you some example of how it can go through. In this example you will see zinc oxide for example if you operate with the discharge voltage of 16 k v and external capacitor of say 26 nanofarads then what you see here is stoichiometric film but many particulates are there lot of small solids are seen on the SEM surface. But if you are going to change the discharge voltage and external capacitor you would see for 14 26 combination stoichiometric film is there and it is smooth and very low number of particulates are there and you can also see the same combination works out for calcium phosphate, zirconium tin, titanate, barium strontium titanate. In all these cases with the proper combination of your discharge voltage and external capacitor you can actually have a very smooth film coming out. This cartoon tells us what is the gamble with the stoichiometry. So in such conditions what is the stoichiometry of the final film for example in this case this is a RBS Rutherford back scattering spectra of your calcium phosphate which will actually estimate how much of calcium is there how much of phosphorus is there and how much of oxygen is there.  In the case of PED film you would see that there is a very good match and both in the high energy region as well as in the low energy region but notably you would see for a PLD film there is a problem of mismatch for phosphorus even for calcium here and also there is a tailing in the low energy spectrum that is for oxygen. What does it mean compared to PLD? PED seems to give a very good film stoichiometrically and that you can see from the SEM micrograph also these are the small particulates that I was mentioning in the previous slide. So these sort of small particulates are there but very minimum compared to PLD process and therefore for complex materials PED seems to be doing a better role and similarly if you look at zirconium tin titanate ZST the RB spectrum is given for both PED deposited and PLD deposited film as you can see here in this case there is some problem with the oxygen stoichiometry here but titanium and zirconium seems to be doing pretty well and if you look at the PED oxygen stoichiometry is actually guaranteed there is no problem here as a result if you look at the SEM micrograph of the PED deposited film here and the SEM micrograph of the PLD deposited film you can see how the grain structure differs. In other words this surface seems to be relatively much more finer and smoother than the discontinuous grain growth in the PLD structure. Therefore there are lot of advantages when we specially play around with complex materials PLD because of the energy takes that is involved it seems to have an edge over the PLD process. In the case of PED the mechanism of interaction with the target is governed by electrons and not by photons which is the main difference and thus the energy transfer to the target material is much much more effective in a PED process compared to PLD. So wide band gap or highly reflective materials can be ablated with PED and this is one of the reason why polymers can also be easily ablated using PED method. In the case of wide band gap materials such as calcium phosphate it is also shown that the surface morphology of the films grown by PLD strongly depends on the target optical properties. So any optically sensitive material they will actually depend on the optical absorption coefficient say alpha and if this alpha is not comparable then the material might throw some plume but it is not actually ablating. So you do not have this problem in the case of PED because it does not depend the target does not depend on the optical absorption coefficient just depends on the beam current and as a result beam energy. Therefore it is very easy to deposit optically active or materials which are optical materials. So this is one of the reason why PLD is more favored. I would like to give another example of zinc oxide that can be deposited with PED. Deposition of zinc oxide is actually favored in substrates like alumina because alumina oxide in this case is actually sapphire we call as Al2O3. So you can deposit zinc oxide on alumina reason the zinc oxide is also HCP and it can easily grow on sapphire which is also HCP and if you look at the growth you would see only the 002 or 004 reflections of zinc oxide which means it is a C axis oriented growth. So zinc oxide is actually growing on the C plane of your sapphire substrate therefore you would see only reflections of that and the way you see the intensity of your C axis grown zinc oxide it clearly shows that they are very highly oriented thin films and you can make epitaxial films out of it. If you look at the cathodoluminescence that means you are trying to excite this zinc oxide film using a cathode then you can see this emission which is very typical of zinc oxide which approximately comes around 380 nanometers corresponds to 3.27 electron volt is clearly seen and this is a very useful input you get a very sharp emission although there is a camel back here which is approximately of the order of 550 nanometer and this camel back is usually due to the oxygen non stoichiometry nevertheless the band to band edge emission is very clearly seen using zinc oxide. So you can make very good highly oriented zinc oxide films using PED as I told you in the previous slide this zinc oxide can be easily made with very high degree of orientation. There are factors that we need to bear in mind when we deposit zinc oxide for example the beam energy parameter is actually given by this relationship and it goes as E is equal to Cu square by 2 where C is your capacitor and U is your discharge voltage. So for a capacitor external capacitor of 26 nanofarads and beam voltage of 16 kV you would end up with a beam energy of 3.33 joules. So if this were the case then you see several particles are there in this film and this is not a smooth film therefore this is not good for sensing properties. So what do you do?  Suppose I reduce the discharge voltage from 16 to 14 then E2 will be just 70 percent of your E1. So considerably you can bring down the beam energy from 3.3 to roughly around 2.9 joules and once you do that you can clearly see the smoothness of the film changes quite a bit. You can see here in B all the particulates are now vanishing and very few particulates are there. So what you finally do? You again try to bring down the external capacitor to 16 nanofarads and for this combination you see almost most of the particulates are avoided in zinc oxide film. Therefore the beam parameter is very important you need to play around with this numbers to get the right response. So the film roughness is very critical to the electron beam energy that you are choosing and based on this you can see how the profile changes. If you are looking at a polycrystalline film for ZNO for example the target to substrate distance plays an important role. If you are going to keep the distance at say 2 centimeter then you are seeing this 3 peak which is characteristic of zinc oxide to be more broader. In other words it is more amorphous. If you are going to keep it at 3 centimeter distance then the crystallinity improves and the best samples are made when the critical distance is at 4 centimeter. Therefore each system has its own sensitivity we need to optimize the distance. This is a SEM image of zinc oxide that is grown on silicon. You can see how sharp interface you can build using pulse electron deposition. You can either make a polycrystalline zinc oxide film or single crystalline zinc oxide film depending on the substrate that you are choosing. And this is another example by Venkatesan's group at Maryland where they made a transparent conducting tin oxide films. Why are they used? Because for photonic applications you can now use a transparent electrode anode rather which can replace indium tin oxide because of the cost that is involved. Tin oxide films are preferred and you can see here PED grown films show nearly 80 to 85 percent of optical transmission. In other words it is almost a clean transparent electrode. So you can get a very good transmission out of a PED deposited one as comparable to PLD. And here also you look at the mapping of your tin oxide using mass bar. The isomer shift is exactly the same between PED and PLD that means you can get a very good oriented film. And here again in B you can see the phi scan of all the reflections of zinc oxide and the rocking curve shows that the rocking curve full width half maxima is less than 1 degree. That means it is a very nicely grown film using PED method. And you would also see how PED is very critical to the processing gas. For example this is a comparison made between PED and PLD. For 8 millitre oxygen pressure in combination with hydrogen you can see the resistivity of your tin oxide. It is fairly low it is nearly metallic with a PLD but for the same 8 millitre with PED you can see the resistance is of the order of 10 power 6. Therefore the purging gas or the atmosphere that you use is very sensitive. So you need to have a optimum for PED process. And similarly one can make very nicely grown film of Gallia which is also useful for upto electronic applications as you can see here. This is not exactly a single crystalline film. This is a poly crystalline film grown on sapphire substrates. And LASR MN O3 in the last lecture I mentioned how manganite films can be nicely grown and they show that critical metalinsulated transition same as the case. But again gives you an idea how the transition metalinsulated transition can change with the gas that you use. In this case PED in argon gas gives you a metalinsulated transition which is shifted by nearly 50 Kelvin. Whereas if you deposit this in gas in oxygen atmosphere you get a room temperature metallic film. So we can make even manganite films with ease and this is the deposition chamber that we have at IIT. This facility is there and we can try to grow films of a variety on a variety of substrates. So this is the processing chamber and this is the 6 target carousel that we have and the whole thing is actually triggered using a computer. You can trigger the electron beam source and this is one of the pictures taken at IIT Kanpur where you are ablating manganite films and this is the typical plasma that is generated during the process. I will give you an example of how a polymer can be deposited. PTFE is a well known polymer which is called Teflon and to ablate a material like that is impossible using PLD because of the optical absorption coefficient which is quite quite different. As a result it is not possible to ablate that easily using a PLD process but you can see in PED you can deposit such a film and room temperature grown film shows the X-ray pattern which is typical of the target and suppose you grow the same film at 100 degrees C you see a amorphous state and that is what you see from the TEM also you have a crystalline film pattern emerging. How do I know because you are controlling in nano size it is very difficult to know whether you deposited any film or not. If you are going to deposit on a Teflon coated glass this is the Teflon coated glass and this is on water droplet glass and glass you can clearly see that the contact angle changes in the Teflon coated glass meaning you have made a very effective coating of Teflon on the glass. So you can also see the IR very clearly showing that PTFE can be made using PED and in room temperature it gives a CM feature like this but when it is going to 100 degree C you can see a considerable loss in the fluorine content therefore it is not really Teflon but it is actually a non-stratiometric polymer film and this is the SEM of the target you can see a very nicely cut solid surface of a polymer and the microstructure changes when you try to deposit this film with different temperatures and this is another example of how the crystallinity of the polymer varies from room temperature to 100 to 300 and to 500 although the X-ray remains the same it is very tempting to conclude that I am making PTFE film but as you see here you go down this SEM features you can clearly see the microstructure changes which means when you deposit or when you post anneal this films at higher temperature you are actually losing quite amount of fluorine. So care should be taken to optimize the condition and if you go to 500 actually the compound has transformed into mere carbon. So what you see here is nothing but carbon so we need to understand this dynamics closely when you deposit PED and it is also possible for us to gauge what is the thickness of this film that you are making and using a profilometer it is possible to measure exactly the thickness of your PTFE layers. This is a typical AFM image of the film and we can also do some nano structuring you can write IIT Kanpur as a nano structure and length and width of each line is 1 micron and 44 nanometer respectively. So you can actually do this sort of writings on polymer films it is possible once you write using electron beam you can try to cap this with any sort of dopants. So you can actually try to fabricate any device by nano structuring this polymeric surfaces and this is another effort where you can use PED to make devices. I want to make a spin tronic device then I can actually go through this protocol I first take a glass electrode like this 5 mm by 5 mm and I can put a stripe the first black stripe what you see here is nothing but iron stripe and on the iron stripe I can actually put a PTFE square layer and then on the top of the PTFE layer I can put another iron stripe. So this is iron electrode and iron electrode and PTFE is sandwiched between two iron electrodes. So the AFM of each of this layer is shown on the top you can see the microstructure is varying the microstructure of the top electrode is quite different from bottom electrode because you are heating this sample during deposition at 250 degrees therefore you get a fine grained structure compared to amorphous room temperature grown film. So once you make this film you can actually measure the resistance by applying voltage across these two ends and you can measure the you can apply current across this and measure the voltage across these two leads. So this way you can make a plot of resistivity and before that if you take a look at the individual layers you can see the bottom and the top layers do show different coercivity and in a device they typically show this two step loop and this two step loop is very critical or characteristic that a device is made meaning the electrons are now tunneling through the polymeric layer and only then you will see this sort of a two loop situation but if you actually measure for that device with the polymer thickness varying from 3 nanometer to 4 nanometer what you really see is pinholes which are short circuiting the top and the bottom electrode as a result you get a magneto resistance which is negative in nature. If it is negative that means there is a short circuiting between this electrode and this electrode via pinholes which are formed by PTFE therefore this is not the desirable one therefore what I can do is I can increase this layer thickness of PTFE which is in the middle and if I increase it to say 6 nanometer then I immediately you see the magneto resistance switches to positive in nature which means the device is actually operating. So this is a very useful information to understand how PED can be used for making critical devices it is not just making films you can make devices and how do I know that I have made a device if you actually do R versus T plot typical values of your resistance has to be something like this say 95 ohms what does it mean the ion electrodes are actually dealing therefore resistance has gone up if through the pinholes they are short circuited the resistance will be less than a ohm it will be in milli ohm that means both the electrodes are in contact with each other therefore resistance will give you a useful map whether your device is really flat and it is working or not. So PED can help us make films like this and this is incidentally one of the good examples of a tunneling magneto resistance curve. Lastly I would like to show some example of yttrium barium copper which is a superconductor and how this can be deposited and chrysanth group have reported how this can be made not just as a film but as a tape because for practical applications you need to use it as a tape and this is the profile where they have used it as you can see this is not just a substrate but this is a polymer tape material called rabbit so rabbit tapes are nickel tungsten tapes which can be rotated like a reel and as the reel is being rotated you can try to deposit yttrium barium copper on the substrate and therefore you can do a reel-to-reel deposition which is one of the biggest advantage with PED process this cannot be done with these with a PLD instrument so that way you can actually make a substantially good application oriented deposition using PED and you can also map depending on the pulse time deposition time how the composition varies this should be your actual composition 1 is to 1.6 is to 3 for yttrium barium copper and as you are keeping on pulsing you can stop at some counts and see what is the composition as you would see copper does not suffer in stoichiometry but there is a given take between yttrium and barium as you keep on progressively depositing high Tc films so you need to have some idea how the chemical composition can vary and also the distance between target and the substrate is determined if you are going to keep it at 6 centimeter you can see the Tc is varying as a function of millitor of oxygen partial pressure if you are going to keep it at 7 then you can see you can achieve a good stoichiometric film even below 50 millitor so all this are very sensitive and one depends on the other therefore depending on the system we need to make a compromise and these are some of the superconducting films these are the actual plots of yttrium barium copper oxide as you see a typical superconductor will show a metallic behavior and then it drops down to 0 shows absolute resistivity at 90 k and such films can be easily grown with PED technique so in one sense we can sort of map to understand that for various compositions you need various mapping if you are going to use alumina target probably the distance or the target mount has to be like this if you are going to use a copper plate then you need to have go for a probe like this so different mounting approaches are also useful depending on the sort of material that we are using and this also gives us some idea about the peak signal and the number of pulses as you can see here you can easily do it for copper whereas when you go for alumina targets the ion probe peak voltage is fairly low and if you want to achieve one hang strumper pulse then you need to sufficiently go for a compromise even on the target mounting approach so all these are very important when we try to look at PED process so to sum up some word of comparison between PED and PLD PED is having its own limitations in terms of the stringent parameters that are critically linked between each other for example target distance the amount of or the millitor of the gas that you are using the nature of gas that you are using and then the probe voltage electron beam that is coming and how the distance is kept between the target and the substrate all these are very sensitive in case of PLD this is not too critical though the partial pressure of the oxygen or organ is very critical in PLD process so with the fair amount of understanding it is possible to extend PED process to a variety of useful applications and therefore more studies will be done especially for device applications using PED so with this I stop.


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Hello, thank you for joining me. Good morning from a very very cold Riga. It's minus seven, like an ice rink where I am And we are just going to the main railway station. We're catching a train today to Sikorda They told it's a nice town, about an hour from here. There's a castle there, there's a cable car there So it should be quite an interesting place. There we go. There's the main railway station Very sort of Soviet looking I believe that red writing up there says Latvian Railways. This is going to be my first experience of the Latvian Railways I've travelled from the tram to the Riga, not yet been on one of their trains. So let's go and have a look see what we're going to find Just bought my ticket, just getting myself coffee. I love these coffee machines. They're all like a Euro or Euro 20 And there's my coffee being made for me. I find it quite amusing at the end. It just sort of drops the stick in for you to stir it when it's finished So when I've got this coffee, I'm not sure if there's going to be any catering on the trains. We're going to go up and have a look at the station See what there is. Probably a time to have my train arrives. The coffee's nearly finished pouring out Most of the trains are quite... Just dropped that stick in the end. I was having that amusing. I know that's just me. Anyway, yes, most of the trains I've got are Soviet-era EMUs, mainly EMUs. They look quite good fun though to ride, so I'm really looking forward to it So this is the station. That was the ticket office just over there. I've no idea where I'm going to find them when we go up here I haven't been to have a look at the station yet. Usually I do, but spent so much time tram-bashing Haven't got round to going up here to see what they've got Love we're going to see these local trains. I don't know, you might see the old freight passing through I'm really getting excited about my first proper experience with a Latvian railway So there's an old EMU part there. Let's have a look over here Probably when you've got a camera in one hand and a coffee in the other Can't get yourself outdoors. I wonder if that's our train. That's an electric, very Russian looking It's going, let's watch this go. So that's just gone. There's another EMU there And then this, that one's going as well This looks like, this is our train. This is a fun per Now, if you ever travel on fun per's, not that there's any in front line service in the UK On heritage lines, there's one thing you have to do and that is you have to do That's it in the motor car. So what we'll do This is our train covered in snow. Let's have a look what's the number of it DR1AM, yeah it is AM, feels like 1AM 2916 Let's have a walk down because I think that it'd be worth travelling in the front carriage To listen to the thrash from the diesel engine What's going to be like inside? My friends with me, he's just got on there. He's not a rail enthusiast because he wonders why I've got to sit in the front carriage I think it's all covered in ice. It looks exciting though I think I might have gone on one like this in Vilnius a few years ago So this is the motor, the motor car up here So if we're sat in here, I wonder if we'll get the thrash like you would get on the UK fun per This year I went to the down Patrick and Countdown Railways gala in Northern Ireland And I sat in the bumper, the last remaining Northern Irish bumper So this is our beast to take us to Segola This is really exciting. Might not be a local train but this is about as exciting as you can get For a non-local train I'm going to get inside and see what it's like We've left suburbs of Riga behind and we're travelling through forestry Lots of snow on the ground. It's double track all the way up to Segola So we might sit the other train passing But I haven't seen much. Didn't see anything interesting really as we came out of Riga So I'm just going to sit back and enjoy the ride and look forward to exploring Segola So as our train disappears off towards Estonia It goes just over the border into Estonia Here we are. This is Segola It's a lot colder here. There's a lot more snow on the ground This is the railway station So let's have a look It's a bit exciting I think it's going anyway. It's covered in snow. Let's have a look at that And then we're going to go and explore the town So this is a really exciting town to look around It's got castles. It's got some cable cars which I'm looking forward to going on I hope they're going to run in this weather. Even though they might not But we'll certainly go and look for them. Let's have a look at this lava first I think I need to go and get a hot coffee as well There's an old water tower there And here's the lava Classic lava Not long it's been parked there It's on that of the inflate That's a great spot. That's really made my day for it I'm now going to wander off that way and have a look around the town So here we are now outside the front of the railway station It's really cold here. It must be about minus 10 There's signs everywhere about skiing. Ooh, flipping a bit Ski resorts. It's very much a winter sports town Look at all these big piles of snow. I don't know if someone's done over there Someone's actually, I'm not quite sure if it's for, if you have a toboggan But someone's actually in this huge, huge round of snow Someone's carved steps into the snow. Look at this So these steps won't be here. They'll melt eventually I'm just walking up these snow-carved steps I don't know if the idea is you're supposed to, it's like a mini ski slope Because, yeah, then there's like, I think that's the point That you're supposed to come up with toboggan or skis And slide down to the railway station I don't know. I think I'm probably going to walk back down And there's some quite nice looking cafes over there I really need a coffee to warm up I just had a nice coffee and mid-morning snack at a cafe called Mr Biscuits I've now followed the railway line along there Because I saw something from the train Which made me want to go and take a closer look So the railway line is just there behind those trees If you follow the road through the snow There's that building there And it's got the Latvian flag flying And coming out of that building is something a bit unusual Not the sort of thing you see To start off I thought it was just a hotel But look, there's lats coming out And it goes all the way down there There's a bobsleigh run There's a van coming up So we're not really in a mountainous area Latvia doesn't have mountains It just has the sort of weather everyone associates with mountains So they've got this bobsleigh run It'd be great fun to see it in action But I don't think we are today You can see there's a huge gorge down there And there's a river So I've been told there is cable cars here My family's now to follow that road that way At the fork Not follow the railway to the station But go that way along above the gorge And you'll find the cable cars there I've just walked right through the town centre There's a ferris wheel there Now I've come to an area This isn't the cable cars looking for But this is where there's quite a lot of winter sports activities You can do And here there's a ski slope There's also one of those bobsleigh runs Now unfortunately it's not running today So we won't be having a go on that But we're going to have a look I'll have to come back in the summer Everywhere I go I find I've got to come back to But I think the cable car did want to do Should be running an outtakes across the gorge Which I'm going to show you properly in a minute So we get up to here And here is a board Showing all the activities you can do Now see this lady here She says I'm in a great time on that bobsleigh run I'd love to do that But it's not running It must be because of the cold But I think the idea is you go down a bit You come back up on the cable car I went on one like that At Lake Bled in Slovenia in the summer The cable car chair is trouble As you can see it's not running So we're not going on that But what we're going to do We'll go up to where it goes If we were going on it Because The view is pretty impressive Look at that That's looking down onto the gorge So as I say this is not mountains at all It's just them in cold Cold in a nice way Fantastic view and look Skiing is taking place Have you got the drag lifts or the skis? They aren't working But I'm not running any good at skiing I've tried snowboarding once But it's not running my thing But I'll be like See that person there Looks like they are struggling I think So I'm not going to go skiing But the bobsleigh run Look it starts there So you sort of sit on it Like a motorbike It's like a monorail It goes off down there And then you pretty come back up On the cable car I think what we're doing now We'll go over there And have a look at the view That way over the valley So with the cherry in the background We're walking through the snow It's getting a little bit deeper now But we should get a really good view It's like an interesting looking house Over there Mansion on the other side of the gorge We come to here You can see It's like people would sit here In the summer And enjoy the view I'm pretty not going to sit here Too cold for that one Certainly going to enjoy the view And we go through here And wow There we go See the road down there I don't think this one's a ski slope But you can do some really nice hiking trails Around here I'm probably going to stay on peace today It's amazing I do really like snow It's cold But it's bitter But I really like it I keep seeing this everywhere It's like the S for Sigolder It's like the symbol of the municity I met a lady actually At the station She saw me filming And she said she was from the tourism And she said it's great here So do come and visit Sigolder I'm going to continue probably that way I'm going to go find the cable car Which I hope will take us to the other side of the gorge I've now come a little ways from where the skiing was We get to here Look it says Sigolder Adventures In the cable car Goes off over there Now it's interesting I've not seen one quite like this one There's only one Usually one goes one way One goes the other way Or you have a few of them On like a cyclic Cyclic system This one There's just one Here's the one cable car So I think they must Every now and then Send it across the gorge There it is So I've never quite seen one like this So we'll have to find out It'll take us to So there's that castle Or mansion over there I think it'll take us to over there So I'm going to have to go and find out If we can have a ride on it or not I hope we can I've got my ticket and we're getting on This is going to be quite exciting A ride Over there Across the gorge So here we are This is the interior Of the cable car That's not real snow It's going to be fun There goes the little cable car Making its journey back across the valley I was chatting to the driver on it So there's one cable car It goes back and forth And the driver She sits in it And takes you She sells you the ticket She gets in She must go back She told me a really nice story As to why they built this cable car 54 years ago What happened was One gentleman lived on that side Of the gorge His girlfriend lived on this side Now it's a walk You can do quite a pleasant walk I've seen steps going down So he'd do that walk Which was all well and good But when it began to rain And it was cold at night It wasn't so much fun He thought, wouldn't it be nice If I could fly across Like a bird And then he built this It's the only cable car In that fish, she tells me And it's just sort of Unusual and different I've never been on one Where there's just one cable car Usually there's a few of them Like I was saying on the other side So that's going to make its way back It really does drop quite a long way And climb up I would have filmed in the cable car But they were playing music And you can get into trouble with copyright So I was unable to film In the cable car for those reasons What I'm going to do now I'm going to have a little walk around It's very cold And there's not a lot going on She says there's a cable Which is kilometers walk away I think I'm going to leave that For a warmer day That said, if you do come here If you come here in the summer It can be quite a long queue To get on the little cable car Just like it's a lookout tower I don't think we can go up there So bear that in mind If you want to come here It's quite good coming here at winter You get to face yourself There's a ruin of a castle there She says there's I was told there's three medieval castles In this area There's this one There's a red one Which I can see from the cable car And there's another On the other side of the valley Which we'll have a look So over there We'll go and see the castle So that's the cable car Over there You can see the castle We're going to have a look at that But look at this Pretty cool Lapvin building It's very traditional What you get in this part Of northern Europe If you have a look You can see the wooden Well it's interesting Because it's made of stone Clearly And then you've got This wooden part here I'm going to guess That sign there's private So I'm not going to go any closer But it's such a nice building And I love the veranda Or balcony it has All along the front What we'll do now We'll go and look at the castle So there's all sorts of hiking paths everywhere It's very cold But very pleasant to walk along The one that goes down That way into the valley So what I could have done As I was saying You can walk across The Down into the gorge And up again Because there was a cable car I went on that We're now going to cross This bridge And go and have a look At the castle I can't find any information On this castle There's no bordering But I'll find out Something and I'll I'll put it Into the video So Let's cross this I think it's a completely Wooden bridge You just can't see The ground Because of the So It's just like a Like this It just makes it more exciting There's not a lot To see of this castle I think there's more To see of the other castle On the other side Of the valley Because One sort of guess Is that they would have been Defending the valley In medieval times For whatever reason And a bit like You get others in Wales You might get free castles All very close to each other So some ruins up there Let's just see what's Over there As I said There isn't a great deal To see I expect Looking across All of that Would have been Part of the castle once But now It's just all Stones And Snow And trees Not over there If we go up here There's arches over there I want to see if we can Should see something A bit more interesting Over there It's just so cold now If I wasn't walking around If I had to sit down I would be freezing It seems that this time of year There's no Where to get a drink Or anything on this side Of the river So it's kind of like Well, the lady said She'll be back In half an hour So As soon as I see that cable car Coming back I'm going to go Back on it The funny thing is It costs 16 euros To go on the cable car Which is Maybe a little bit expensive But it's definitely worth it The train journey Your return train journey From From Riga to here Costs only four euros So it gives you An idea of the difference in prices There's a A door down there I'll see if some stairs I want to go Around there So we can get inside Let's have a look Can I No, I'm not I'm not going down there If I walk Over here It's probably It's a bit dangerous It's probably snow You can't see Where your foot and your foot Is this a drift Or is it A stable ground For a walk I think this is alright I want to see what's in there I can just see There's a door Definitely Room Or something So if I can go to that We'll go and have a look There's the castle What's left of the castle What I'll do I'll do a bit of research Find out about the castle And I'll tell you About the castle now So I'll just A little bit of info On the castle itself I think If I go down here I should be able to get in I think what it's going to be It's just like a little staircase In the wall So we can do that We can get down At least get over I can see other people Have been Down here I'll go to hip And Ah, yeah It's not The stairs Are down there But we might as well do it So here we go Yeah Not far Inside We are inside the castle A little window Going out there We get to here And We're up there a moment ago There's another I think that's just a It's not a Let's have a look at the window And then what I'll do I'll leave this bit here And I'll walk back to the Cable car So here's a view How the window to the castle Is back at the cable car now I can just see it coming Back across the valley I've worked out now How it works If you have a look You can see there's The very thick wire That wire doesn't move That's what the Wheels of the cable car run on The one below that Is moving this way And you can see Maybe you can't see But there is one above it If you look up there There's a wheel You can see the wheel Is feeding out So it's like a big Cycle Of Like a big wire Is going round And round and round So as it goes that way It pulls the car this way And then the other way When it goes back So I'm going to stand here now And wait for the cable car To arrive to take us back Across the valley So we're back on this side There's our cable car There's also a lift here So if you are in a wheelchair Then you can ride it That's good to know Now there's another cable car Which I'm not going to do today But see that thing there That Two people Hang down And they go over their own weight And you can fly out Across the valley So I think there's only one wire That cable car will be on the other side So you fly out across the valley And then the cable car Pushes you back So I think that's Yeah If I want to take that off the haulage I'd have to Have a colon that So that would be really fun Anyway, we're back over here There's a castle around the corner I'm going to go and have a look at that now After our trip across the gorge Back on the Segorda side Just having a look now Firstly there's a frozen pond over there I'm not going to walk across the ice Here is the town's Paris church So we'll have a quick look at this And then Not far from here Is one of the castles So we'll go and finish off Up at the castle Now we're inside the church It's a Lutheran church A tower Was built in 1929 So here we are This is I quite like the sort of plainness Of it But in a way the plainness Is what makes it Really quite nice I do like it You've got the organ And looking down the church There's the pulpit up there It's quite high up I went in an Orthodox church yesterday In Riga city centre But you couldn't take any pictures So It was It was very nice But in a completely different way And it was very elaborate This is just nice And quite plain But I do Really like it There's the Mabien flag there Just come down to here There's something Here Quite interesting Not something you can See in the UK church But there's a load of wood Stacked up This is really interesting Heater Look at that Now I'm not sure How it works But obviously There's a chimney there And there's All these They're pushing out But there must be Some sort of filter system Inside I've never seen a heater Like this before But it's really cool So you must push out heat But no fumes So all the fumes go up there And it's really different What I've seen before I think if I went to church People did just sit here Just to marvel at the heater So yeah I don't know anything about that one Oh no I've sussed it I think I've sussed it Look Down there I reckon that It sucks in the cold air Down there And then The cold air goes round those pipes And comes out there And then the fire burns inside And all the fumes go up there That's it There's no fumes coming out So If I put my finger there I can feel a tiny little draft So that's it I've sussed it I'm going to go now I've got one more thing to do I've got to go and find a castle We're having warmed up in the church By the best heater I've ever seen I'm now back out in the cold And as promised We're going to go and look at the castle We're actually going to go and look at two castles Because in front of us here This is the gateway to the new castle The castle we can see from the cable car Is behind it That's the old castle So we're going to walk into here And we'll have a look See what we can see See if there's any information to Tell us what's where Oh yeah, that's helpful Look, there's a map So we're there We'll walk up there Have a look at the castle And Oh, the wooden manor house That's that Really nice red wooden manor house We're going to have a look at that And there's also signposts So yeah, wooden manor house New castle And then the old castle ruins That's what I was looking for So I suspect if you came here In the summer This would all be really quite pleasant gardens I see where it does remind me of Where I have been to Another castle in Europe Is Keste in Hungary It's got some nice gardens Like that And there's a castle If you want to see that video Have a look at the link on screen now I've never been there in winter Let's see it like this So that's the wooden manor house It's a bit like the one we saw On the other side of the river That traditional wooden house I think it's really nice Something you've seen This part of northern Europe And then there is the new castle And then behind is the old castle So we'll have a one bus See what we can see I think there is A souvenir shop and everything And maybe there's a cafe And information over there I've been told this is where The tourist headquarters for the town are So this is... I really like how the The red Stands out so much In this snow It's quite something And there's another S.I.S Sigourde with an exclamation mark The old castle's over there So what we'll do I'm just going to have a little Wand around And then we'll go behind The new castle And see the old castle So we're now around the back Of the new castle in Sigourde And around here That is the old castle Very impressive looking I'm very excited To go and have a look What I'm going to do I'm going to put that in A separate video So have a look at the Encore screen now To see in Sigourde Old castle So I'm now on my way back To the railway station I've really enjoyed Looking around Sigourde It's a very pleasant town And certainly with this snow Lived up to being Latvia's little Switzerland So if you're ever in Latvia If you're in Riga Do get the train out to Sigourde I think it'd be interesting To see this town in the summer Look very different There certainly wouldn't be Massive piles of snow everywhere And I expect to go across the road Not a nice little park here Of course that'll be green grass It feels hard to imagine that as Green grass It's good how You can see how they've been around Keep seeing people going around Clearing the path It's hard to see in the camera But they have cleared the path To make a nice path To walk along So it's not like you're Continually treading in snow Not knowing where you're going So here's the little green grass I hope you enjoyed this video I'm going to head back to the station now Caps were trained back to Riga Thank you very much for watching Please do feel free to like, Subscribe and comment And from the beautiful Latvian town of Sigourde Goodbye