Remember what we discussed yesterday? So, what materials we can use for solar cell? And we cannot use metal and insulator for very good reason. What else? We can use the combination of materials to get a base optical and electrical properties. And how to tune the tuning of the band gap? Metal tuning is we can do. Why we come to the 14 percent? All the way from 100 percent we have looked at the various losses in terms of the transmission, in terms of the higher energy photons, in terms of the recombination and some other losses that will happen at the junction and the contacts. Very nice. What else? Challenge in the PV cells. Any technology, any solar cell that you want to develop in future, you must be take care that it has smaller energy, payback period, smaller money payback period, material is abundant, there is a lot of efficiency are good enough and things like that. Yeah, sorry. The fill factor and the open circuit voltage and the short circuit current and that reminds me of the homework that I have given to you. Thank you very much. You done the homework? No? Ok fine. So, today was just introduction, you know, what are the possible issues that actually goes with the solar cell. And today what we will go is little deep into the theory. Again it is a it is not a complete thing because the whole P N junction theory takes about 8 to 10 hours of discussion. So, this is again not to be going to be sufficient, but it will get a kind of basic idea how the solar cell works and therefore, what we are discussing yesterday, you know, how to generate up, how the voltages get generated, you will make little more clear from the today's lecture. So, we look at the P N junction theory. So, what we are going to look at is this basic points, the carriers, the drift of the carriers, diffusion of the carriers, generation and recombination. So, these are the four major things that happens. Drift of the carriers, diffusion of the carriers, generation and recombination. This is how you define the device operation. In any solar cell, these four things are happening all the time always. And we need to understand this process is very well. So, that then we can actually design a new kind of solar cell or even if solar cell is not performing well or if it is performing well, we can understand which of the process is actually contributing to the good performance or not so good performance. And again, then we will try to look at the IV equation of the diode in a very qualitative manner. The quantitative description or the proof requires little bit more time, which we do not have for this workshop. But we look at the equation of the diode and then we look at the equation of the solar cell, which we are ending at the point we ended yesterday. So, the carrier drift and diffusion, these are the two forces that acts upon charge carrier or the carrier simply a particle, which results in the motion of the charge particle or just the particle. Drift is a phenomena that happens in presence of the electric field. The carriers moves because there is electric field. In and in our solar cell, the electric field does not exist everywhere. That is our only at the junction, this is electric field. And at the other part of the junction, there is very weak electric field. So, they will see how it works. The diffusion is phenomena in which carriers move because of the concentration gradient. So, that is a force. The force behind the motion of the carriers due to the diffusion is the concentration gradient. Generation, as we have seen yesterday, we will look at little more detail, what is the absorption coefficient, absorption length and how much what should be the absorption coefficient and what is the material thickness requirement and so on. And then the recombination, what are the various mechanism by which the carriers recombine. We have seen yesterday, but we will go little bit more into detail. And then qualitatively, we will try to put the equation of the diode, p-n junction diode and we will modify it for the solar cell. So, that is the agenda today. In any semiconductor, the electron is moved. So, E is electric field here. By the way, I wanted to make one correction before we go further regarding yesterday, we had actually get the approximate value of h nu. And I wrote that it is 1.124 lambda in micrometer. Well, this is wrong. The correct answer is 1.24 lambda in micrometer. From this calculation, the highest photon energy was coming to about 3 sorry, 3 electron volt and the lowest was coming about 0.28 electron volt. From this calculation, the number I think will become about 3.5 electron volt and the lowest is about 3. something electron volt. So, this is actually not 1.124, it is 1.24. That is correction that you can make. When this has come simply from putting h nu, nu equal to c or lambda, you put the value of c and put the value of h, the Planck's constant you will get the value which is 1.24 and lambda in the micrometer. Nothing great about it. So, in any semiconductor, if you are not putting any electric field applying electric field, another thing is this E is actually normally used many times for the potential energy and this involves zeta is used for electric field. So, this E here is actually electric field. So, even when this electric field is 0, the electron is moving all the time. Why it is moving? Why it moves? The electron is moving all the time. So, this is electron, it goes here, here, here, random motion, it is going all the time here and there even if there is no electric field. Why do you think it moves? It keeps on moving all the time because of the thermal energy. It is still at even room temperature, it still has enough energy to go around, but the net motion is 0. The net motion is 0. Therefore, if net motion is 0, which means what? Current is 0. No charge transfer per unit time. So, dq or dt is 0 and therefore, current is 0. So, without electric field, the net current is 0. When there is a non-zero electric field, when you apply some electric field, this electron will experience a force and it will still go through the random motion, but there is a in total there is some motion happening which is in the direction opposite to the electric field. Force in the electron is in the direction opposite to the electric field. Is that clear to everybody? If I take a big positive charge, this is the direction of the electric field. If I keep a negative electron, it will move in this direction. So, this is the direction of electric field and this is the direction of electron one. So, the motion, electron motion is in the opposite direction of electric field. So, what you see here is this electron is actually going through the further. So, it is not straight path because why it is colliding with the available the electrons in the particular semiconductor. So, it is not going to the straight path, but it assumes some certain velocity in the direction opposite to the electric field and that velocity. So, at the time it takes from going to here, that velocity is an average velocity you can say because it is going here, here, here, here. So, it assumes a certain velocity against the force which is there because of the non-zero electric field and that velocity is normally referred as a drift velocity. That velocity is referred as the drift velocity. So, you can see there is a force which is equal to in the negative direction because of negative sign electric field and the electron accelerates and de-accelerates, accelerates and de-accelerates. De-accelerates because of the collision it is going through and as a result it gets the average drift velocity. So, now there is some current flowing because there is a net displacement of a charge from one point to other one there is some current flowing. Let us say the concentration of electrons in that particular case is n. Can you write the expression for the current? Write it, what is current dq or dt? So, you need to write how much how much charge is flowing per unit time and you should get the divided by the time and you should get the current. Can you write the expression for the current? So, what you want? You want the expression for the current which should be this. So, what I said how many charge are there? You can assume a concentration of let us say n, let us say electrons are moving. So, n electrons per unit volume. Normally in a solid you give concentration n electrons per unit volume. Now, if I multiply with the charge q then I am having n q charge per unit volume right. Ideally what I need? I need charge per unit time. If I multiply this. So, if I multiply this with velocity drift velocity then what I got? So, this is per unit volume centimeter q and this is centimeter per second. So, this will cancel out, we will get 2 here and if I multiply with the cross section area which is in centimeter square. So, this will get cancelled out and this was having the unit of charge. Now, I am getting the per unit time right. This was having unit of charge coulomb and this is per second. So, what I got eventually? n q v d and this is having unit nothing other than the coulomb per second which is the current. So, if in any case if there are concentration of n particles per unit volume moving with the velocity v d across the cross section area. So, I have a also from here across the cross section area a then the current that will be flow in that condition will be n q v d a that is the current that I am. Now, this current is because of the drift. So, you can call it I drift n I assume that the particle is electron here n right. So, you can say I drift because of the electron right is it clear? Now, same thing can also happen with the force exactly same. So, just coming back here if the direction of electric field is this the motion of electron is in the other direction. So, the electrons are moving here electrons are moving here and because electrons are moving in this direction the current is moving here ok. So, direction of current is same as direction of electricity. So, there is no negative sign same right direction of current is same as the direction of electric field is that point very clear to everybody ok. Now, look at the holes put a electric field here the hole force will be there and therefore, current will also be in the moving in the same direction. So, again the direction of electric field and the direction of current is the same for the holes also ok.  So, my expression for the drift of holes will be same p q v d a. So, the drift current is similar to the the the drift current for the electron and drift current for the hole ok and direction of the current for both electron as well as hole is in the same direction as the direction of electric field clear. Everybody, direction of the current for both electron as well as hole is in the same direction as the direction of electric field yes or no yes everybody not everybody seems to be coming as area ok. I am considering cross section here because you are consider the volume right. So, if I take a cross section here they are like this. So, this is the area this is the where the electric field is applied. So, this is the cross section area. If any doubt please ask we have lot of time no hurry if you are not asking I am going to ask you the question. So, you cannot be neutral you have to this side or this side like bush you are with me or you are against me cannot be neutral is that clear the expression for the right current is very simple you can write drift current expression for any other situation very simple you have to just say how many charges moving per unit time over a cross section area ok. So, very simple now this is expression this is in terms of current, but you can also write I drift per unit area you will get p cube V d. If you are writing this then what is this current density current density per unit area and many times we in solar cell we talk about the current density like yesterday when I told you that I see I told you current density. So, how much current is flowing per unit area. So, you can refer it to current or current density ok. These are the same expression we will not go into the detail sorry. So, these are the same expression we will not go into the details, but eventually arrived at the current density the expression for the current density is normally j. So, commonly use expression for the current density is j and I is the current I is the current j is the current density we are considering. So, I mean we have considered because because the force is also in the negative direction. So, the charge on electron is negative and the force direction negative got cancelled and therefore, the net is positive ok. There is a the force on electron it is also in the negative direction and there is a negative charge coming because of the minus cube. So, both cancel out and therefore, in simplicity what we have looked the direction of electric field is the same as the direction of current which means everything is cancelled out there are two negatives in that expression ok. One another parameter which is very very important that we need to define is how much a velocity a particle attains per unit electric field ok. What is the velocity of the particle in attains per unit electric field? Analogy very simple right if there is a runner which runs on a smooth road and if there is a runner which runs on the rough road ok. The runner same runner same strength everything same it will run faster on the smooth road right then the rough road. Is that clear? Same thing will happens to electron also when electron is moving in a crystal if the crystal is perfect without any disorder without any defects without any impurities then it will run faster or the velocity it will attain is higher as compared to the case when the crystal is defected ok. And the examples of the defected crystals are polycrystalline silicon ok example of defected material is cadmium to the right CIGS and amorphous silicon very defected ok. What does it mean for a given electric field? The velocity that a electron will attain in the defected material will be higher or lower? Lower. Just to check it will be lower right. The velocity that electron will attain in a defected material will be lower then the velocity it will attain in a perfect crystal. And it is represented by a parameter called mobility mu ok. So, mu is nothing but velocity or drift velocity per unit electric field. So, in a good crystal the mobility is high in a not good crystal the mobility is low ok. From solar cell perspective we would always like to have high mobility ok. So, this is one of the electric important electrical property right I said yesterday two properties we need to get the best one is optical other is electrical. High mobility is one of the important electrical property that we are always looking for ok. So, when people are trying to develop the materials and trying to get the and trying to get the job done. So, they are actually trying to show that. So, the what kind of velocity that you can get what kind of drift velocity you can get for a given electric field. And this is the parameter which can vary a lot. The mobility is one of the key parameter for a scientist and it can really vary a lot depending on the condition and the defect and the impurity etcetera. So, keep this in mind this is a very important parameter for solar cell right. Everybody will remember mobility what is the unit of mobility? This is centimeter per second this is volt per centimeter. So, overall centimeter square per volt second centimeter square per volt second ok. There is a drift current for the electrons and there is a drift current for the holes. What is the total drift current for both electron and hole right? What is the total drift current? Some of the electron drift current and the hole drift current. So, mobility as I said is one of the important parameter and the various numbers you can see here. The mobility of electron for silicon is 1350 what 1350 centimeter square per volt second and for holes 480 4 germanium 3900 and 1900. The total current density for the drift current density is the sum of the two current density. So, what we have done in this expression is we have used this expression ok. So, is the V D in your expression can be replaced by mu times electric field right. V D can be replaced by mu times electric field and therefore, expression for J n and J p will become q n mu n zeta n q n mu a q I am sorry this should be what is the mistake here? This should be p. So, q mu a q p mu p zeta and the subscript for the mu n and mu p is different because the mobility for electron and holes are different right. So, you can put together the sum of the two current component is this and if you actually look at this carefully this is nothing, but the ohms law J equal to sigma e zeta actually electric field is nothing equal to i is a ohms law right V equal to i r if you do that analysis you will come to the same expression. So, this expression is nothing, but the ohms law. So, what is the expression for and this sigma is what? So, this expression is nothing, but the conductivity ok. So, what is the expression for the conductivity q in the bracket n mu n p mu p ok. So, you can find out the conductivity of the material if you know the mobility if you know the concentration of electrons you can find out the conductivity q is known. If you know the conductivity you can find out the what also you can find out resistivity if you know the resistivity you can find out the resistance. So, knowing the doping knowing the number of electrons and holes and knowing their mobility you can find out lot of parameters about the materials. Knowing knowing the n n mu n p n mu p you can find out the the total current density you can find out the current if you know the area you can find out the conductivity you can find out the resistivity you can find out the resistance etcetera ok. So, far with me everybody with me very good. So, this is one mechanism by which by which electron move the mobility by the way is not a constant it depends on the doping density ok. If you dope more your mobility decreases any idea why? Very simple doping more means you are disturbing it more right.  And therefore, as you dope more and more the velocity it will attain the drift velocity will attain will be lower and lower and therefore, mobility lower. So, therefore, a very high doping level transfer 17, 18, 19 you can see the mobility are smaller for both electrons and all. Mobility is also function of a temperature ok. So, initially if you increase the temperature mobility increases, but after some after some increase in temperature decreases because the lattice vibration starts ok. So, the the atom starts starts starting vibrate and therefore, it decreases yeah doping density means we have p type silicon and n type silicon right and we have just silicon intrinsic silicon, but in order to make a junction we need to make a p type. How do we make a p type? We put boron into it and so the how much boron is there in silicon that is a doping density ok good. So, this is a tensor 15 boron atoms per centimeter cube in silicon. By the silicon what is the atomic density of silicon? In 1 centimeter cube of silicon how many silicon atoms are there? Very easy to calculate, but I will give the number directly. So, 5 times transfer 22 atoms of silicon there in per centimeter cube that is silicon atom density. Now, when we do doping we put boron into silicon that boron doping is normally in the range of tens for 16 atoms of boron in silicon per centimeter cube that is the doping density. So, when you say when there are tens for 16 atoms of boron in silicon we say doping density is tens of 16. What does it mean? How many atoms of boron are there in per per silicon or so what is the difference tens for 16 to 22? So, 1 million for 1 million atoms of silicon there is 1 atom of boron right. Silicon atom is tens for 22 boron is tens for 6. This is controlled while making silicon itself. When you make a silicon, silicon is actually melted ok. So, in melt. So, you are putting 100 or 1 million kilogram of silicon put 1 kilogram of boron. So, then you will get this kind of doping density ok. So, it is controlled while making silicon itself in the melt itself. Boron atom can come can deflate silicon as well as interstation. So, where is the boron going because crystalline silicon is silicon right. So, boron has to go somewhere that. So, it is first of all it is in melt right. So, when silicon is melted at very high temperature about 1800 degree centigrade at that time you also put boron and then you stir it ok. It is like it is like what making kheer mix it properly you know put sugar or whatever you put mix it properly that is it and then when when when the silicon actually comes up and it gets colder and solidifies. From liquid it goes to the solid form within that form it is a very critical state.  How many boron atom 1 in 1 million very small number is still right. If you are doing doping of tens for 16 only 1 boron atom is coming in 1 million silicon atom will have very still number. You can do it by diffusion, but you actually when you grow the silicon is grown in the form of ingot which is like meter and half long 8 inch or 6 inch the diameter. So, that is done at that time it is a different from the diffusion. In diffusion also you actually insert other kind of impurities where you are diffusing you are also doing similar thing. Not really I mean look at the number it is so small 1 in 1 million really small, but still very large. When silicon is purified you know how much it is purified not 99.9 it is purified to this much 1 in billion and then you can make your device 1 in 1 billion atom. It is similar to find 1 foreigner in the Indian population in the whole of the country that is 1 in 1 billion right we are almost 1 billion. You need to purify some of the impurity to that level then only you can make a device. Of course, solar cell is more tolerant to the more forgiving to the impurity. So, you can actually make a solar cell in a higher impurity concentration also. So, 1 in 1 million is also ok and therefore, now people are trying to make. So, this kind of silicon is called electronic grade silicon very expensive, but now people are trying to make what is called solar grade silicon because you are allowed to have more impurities it is cheaper relatively, but the science of making silicon pure silicon itself is a it is a it is a 3, 4 years back it was in hands of only few people. Only 6, 7 companies in the world was doing every silicon everything in silicon know that only 6, 7 people. Now, of course, there are M. M. C, Tokyama, R. E. C. They are the new people they are in more polycrystalline, but earlier people as I am talking about. These are the these are the Mitch Bushy. These are the main players earlier, but now there are many new people are coming particularly in China ok fine. So, drift you know lot about it now you are all expert of the drift mechanism of the charge motion right. Now, I will make a expert of the diffusion mechanism of charge transfer, but these two these are the two force which is always working in a semiconductor. So, diffusion is. So, the force behind the drift was electric field ok. The force behind the diffusion is concentration gradient ok. It is similar to like if I have only half of the people sitting here in this room in the next person comes in is not going to sit there you will sit here right where there is a space. So, it is kind of diffusion happens ok. Other very classical example of diffusion is the perfume. If I spray perfume here right now everybody will know which perfume it is right because it diffuses the concentration is more of the perfume particle here and it is less there. So, there is a motion is always from the high concentration of particles towards the low concentration of particles. For example, you have one condition where all the particles are sitting at time t equal to 0 at x equal to 0 ok. If so, what does it mean? There is a lot of concentration here and there is no concentration here. So, there is there naturally the diffusion will occur and if you allow the diffusion to occur after sometime t 1 you will see the distribution is increased or the time distance and some other time t 2 which is greater than t 1 it will further diffuse and diffuse and if you wait for infinity time what will happen? The concentration will become same everywhere concentration that is the job of the diffusion force that is the job of the concentration gradient that to make everything similar uniform everywhere over a period of time you have to wait for sufficient period of time. That is the diffusion is the force behind the diffusion is the concentration gradient. Now, we have written expression for the current and current density as a for the drift can you write the expression for the diffusion current? Current is always going to be the same right you take drift at diffusion or anything right it is always charge per unit time. Can you write the expression for the diffusion current or what we need to know if you want to write expression for the diffusion current what you need to know? Concentration gradient so, let us say the concentration gradient is d n over d x that is our concentration gradient. Now, what else you need? You need area let us say area is a and n is the number right. So, you need charge you can multiply by the q what is the unit of this expression just find out what is the unit of this expression and we will see what else needs to be multiplied do it quick quick what is the unit of q a d n over d x n is n what is the unit of n per unit volume concentration per number per unit volume. So, what is the unit Coulomb centimeter square per unit volume n centimeter. So, this will go this will become 2 and this will go. So, Coulomb per centimeter square I still need per unit time I still need per unit time. So, I need to multiply with something which has unit of centimeter square per unit time does not it. If I multiply with centimeter square per unit time this will get cancel I get Coulomb per second I will get Coulomb per second right got it. So, basically and that is true also this is some coefficient which is called d which is diffusion coefficient like mobility is related to the drift there is another coefficient called d which is called diffusion coefficient which is related to the diffusion and having a unit of centimeter square per second we can actually derive this also and this is nothing but the expression for the current I for diffusion of electron I for diffusion of electron Q d Q this is a d n over d x ok. Two important thing we are going to do here now. So, let me write fresh again. So, I diffusion for electron is d Q a d n over d x I can also write similar for the following for the holes right d Q a what should I write here? What should I write here? At the corner my favorite students are actually corner students. If the corner students can understand everybody else can understand corner that is idea what should I write here? P right I am writing a diffusion current for the holes I should write hole concentration right. Similar that mobility was different for the holes in electron diffusion coefficient is also different for the holes in electrons I should write d n and d p right. Now we have done one more important thing in the last time while writing the drift equation for the current we have seen what is the force electric field and then we have seen what is the direction of the current and we found out that the direction of current and electric field for both electron and hole is same. We should do the similar exercise here and find out what is the force that is the concentration gradient and for that concentration gradient what is the direction of current? It is important to find out that right got it the problem everybody I need to know whether my my current is in the same direction of the force or is the opposite direction if there is opposite direction I should put the negative sign right let us do it. So, suppose I plot n over x right and this is my plot of the concentration gradient n over x right if I do the d n over x I can find certain constant right fine. So, I cannot point a straight line then there is no gradient right the fact that I have not plotted a straight line which means that there is a gradient concentration is changing with respect to x fine. Now, because of the diffusion my carriers are always going to move from low concentration to high concentration good because of my diffusion carriers are always going to move from higher concentration to lower concentration which is this direction which is this direction my carriers will always move towards the positive x axis in this case ok. What is the direction what is the d n over d x where it is positive d n over d x is concentration gradient is it positive towards the plus x direction or minus x direction the concentration gradient is positive in the minus x direction. So, this is my d n over d x right. Now, where is the current flowing where is the direction current direction. So, this is the motion of electron and current is this direction ok. So, this is my I for electron. So, what you can see here the current for electron is in the same direction of gradient for the electron. So, I should not put any any sign it is perfect because both of the force the current is in the same direction as my force. So, I should not put any sign there it is perfect. So, this equation this equation here is correct got it this equation is correct following me everybody everybody. Now, let us do for the let us do yourself do it for the holes what is happening do we have to put negative sign or not just do it yourself plot the profile for the holes plot the direction of the gradient plot the direction of the motion and see the direction of the motion is in the same as the direction of gradient or not plot the profile first p versus x do not make it a straight line either horizontal or vertical just make a slope curve like we have done earlier see where is the direction of the motion where is the direction of the gradient. So, if I plot p versus x similar the gradient is positive in this direction d p o d x right holes will go from high concentration to low concentration which means this direction moment is this direction and therefore, because it is holes the current is also in the same direction right. So, I diffusion for the holes in same direction. So, you see the force and the current are in the opposite direction right the gradient is in the minus x direction the diffusion current in the plus x direction and therefore, I should put a negative sign here got it. So, very important to find out the right direction for the current motion. So, now, electron drift current, hole drift current, electron diffusion current, hole diffusion current there are four ways current can flow in a semiconductor there are four ways current can flow in the semiconductor and if I tell you any x y z direction you should be able to give the direction appropriate equation for the current with appropriate sign got it everybody very clear. This is nothing, but the expression how the diffusion will actually have the distribution over the period of time equal. So, starting suppose the particles are in the one compartment therefore, compartment at t equal to 0 over the time the particles will start redistributing themselves and if you look at the very long time the particle will be equally distributed in all that is nothing, but the diffusion mechanism and this is how we can derive the expression for the diffusion that suppose this is the this is the profile of the concentration you have n 1 concentration and 1 compartment n 2 concentration and other compartment at a given time the n 1 particle will actually move in the either side there is a good probability that it can go to this side. So, good probability that the electron which are in this compartment can go to this side or that side and we can say equal probability either side. So, after sometime t half of the n 1 particle will be here and half will be here and it is happening everywhere. So, after sometime t half of the particle in n 2 will be here half will be here it will keep on happening. So, what you will see here is the half of the particle over the time t goes to the other side and this way you can actually write the expression for the flux that is the number of particles crossing per unit area per unit time. So, there is a flux of the electron due to the diffusion you can write in the in the form of the gradient you can write in the form of the gradient n x and n x plus delta x. So, this width of the compartment is a delta x. So, you can write the same expression in this form and you actually write the expression of the flux in the derivative form d n over d x that is what we are writing and this is the flux right this is the number per unit area per unit time what we are looking for current. So, we have to still multiply by the q to get the charge per unit area per unit time and then we multiply with the area. So, you get this. So, this expression here is nothing, but we will have the unit of centimeter square per second which is our diffusion coefficient and this is the flux. So, as I said we have to multiply by the charge q to get the number charge per unit area per unit time and you multiply by the area. So, you get the charge per unit time which is current density or sorry current for the. So, this is this is being replaced by d n diffusion coefficient and this is the gradient of concentration and this is what you get the flux right flux of anything is in the number per unit area per unit time flux of anything flux of charge flux of particles. Multiply by the q you get the charge and multiply by the a you get the current ok. So, the diffusion current density right j is expression of density is per unit area right and if I multiply with the area I get i right j is the expression for the current density and i is a expression for the current. So, this is j means area is not multiplied to see here. So, expression for the electron diffusion current no positive sign here you see expression for the whole diffusion current there is a negative sign and now we know very well why there is a negative sign right right we know very well why there is a negative sign. So, there are how many components of current now 4 current electron drift and diffusion whole drift and diffusion. So, the total current in a semiconductor at any given time should have should have all this expression. So, j total is j n plus j p j n is drift current and diffusion current j p is drift current and diffusion current. So, total expression for the current is sum of all this right sum of all this electron drift electron diffusion whole drift whole diffusion there is a total current in semiconductor and under different condition various components of the current gets modified under various condition various components of current gets modified. Now, few important point to note here looking at this expression what this says is minority carrier current can be significant due to diffusion. Let me write one expression for you which we have not covered because the lack of time, but so in any semiconductor there will be electrons and there will be holes always right one is in majority other is in minority right. So, in any semiconductor the electron concentration is given n 0 equilibrium electron concentration whole equilibrium carrier concentration given p 0 and when semiconductor is not doped it is given with the intrinsic carrier concentration n i right for silicon n i is fixed because this is intrinsic case n i is about transfer 10 number per centimeter cube ok. This is fixed for a material n i is fixed for material. So, if I look at germanium n i that is intrinsic carrier concentration different if I look gallium arsenide intrinsic carrier concentration is different if I look cadmium telleride intrinsic carrier concentration is different. So, it is fixed for the material at room temperature what can be proven is that n 0 p 0 is always equal to n i square always equal to n i square. What does it and if I am doing the doping majority carrier concentration if I am doing doping as we have taken example of 10 square 16 boron atoms per centimeter cube it gives rise to 10 square 16 electrons per centimeter cube more or less same which means my equilibrium electron concentration is 10 square 16 ok. Now, if I put this number here if I put this number here. So, my p 0 is equal to n i square by n 0 n i is how much 10 for 10. So, n i square is 10 for 20 divided by n 0 which is how much 10 for 16. So, my p 0 is 10 for 4 ok because electrons are in majority your very huge number of electrons 10 for 16 what is the whole concentration 10 for 4. So, whole is in minority right whole is in minority and the number difference is huge. So, my p is. So, my n 0 is 10 for 16 and my p 0 is only 10 for 4 ok. This is what normally the situation when you start with the silicon for making solar cell your doping is of the order of 10 for 16. So, majority carrier concentrations of the order of 10 for 16 minorities of the order of 10 for 4. Now, 10 for 16 may become 15 17 yeah it is it is not boron it is phosphorus concentration we are talking about the n phosphorus concentration fine. So, coming back to the slides. So, what does it mean the minority concentration is much much smaller right several order of magnitude in this case 12 orders of magnitude smaller right keep that in mind. So, coming back here this is very important point to note with the solar cell perspective that here n if I am talking about electron current density here it is n and here it is gradient of n ok. This number will be large the drift current density will be large if n is large. So, diffusion current density will be large if gradient is large for gradient to be large n need not to be large gradient can be large. So, if my concentration varies from 10 to 10 to 4 in 1 nanometer then my gradient is very large right even my n is not large. So, therefore, for minority carrier concentration the drift current is always going to be small where there is number is very small, but the because the gradient can be large. So, diffusion current can be very very large for the minority carriers and minority carrier plays very very significant role in the operation of solar cell ok. Take a note minority carrier plays very very significant role in the operation of a solar cell and therefore, current due to minority carrier flows due to what drift or diffusion current due to the minority carrier is always because of the diffusion because then diffusion can be large otherwise the number of minority carrier is so small the drift current component of the minority carrier is always going to be very very small. So, the diffusion plays a important role and therefore, minority carrier plays an important role in the operation of solar cell. Point taken. So, we are making some progress towards the solar cell now. So, these are the forces and these are the direction of current you know very well how to how it has come right. Electric field in this direction current is also in the same direction due to the whole drift and due to the again one of them has to be no that is ok. Whole drift and diffusion electron drift and diffusion. So, this is the gradient this is electric field and you can write the direction you can actually put the direction of current right. Let me take a let me take a quiz. So, this is direction of my electric field and this is n versus x ok. What is the direction of electron drift current and electron diffusion current? How many agree with him? How many do not agree with him? You agree with him raise your hands. If you agree with him drift current is the same direction as the electric field ok. So, this is J n drift fine any objections ok. What is the direction of? Diffusion current. So, this this is my plus x direction. So, tell me with respect to this is it plus x and minus x. Diffusion current for electron is plus x or minus x direction. I I just want with respect to this this is my plus x direction with same is same is J n I do not understand tell me plus x direction or minus x direction. So, you are saying plus x who is saying plus x plus x ok. Do you agree with her everybody? No some people do not agree you do not agree ok. There is a confusion. Let us do it a this is very simple right. This is the electron will go from high concentration to low concentration. So, they will go in this direction right and the current due to electron is in this direction and we are interested in direction only. So, this is in plus x simple is not it. The electron will always go from high concentration to low concentration and because my direction of electron is this my current has to be in the opposite direction and that is what I was interested in the direction of current. So, therefore, direction of current is in the plus x direction. So, J n diffusion J n diffusion is in the plus x direction. If this is the case now things can be reversed right it can be this that whatever happens good it is very important to understand. If you understand this you understand a lot yeah, but this is my positive x direction I know it does not matter right. I can say any direction, but more important thing is this is happening. So, with respect to this direction my current is in this direction that is it.  The main thing is the profile. J n diffusion is the direction of electric field. This is this portion from here below is all belongs to the diffusion. Yeah, portion from here to here is all belong to diffusion ok. Go ahead should I go ahead ok. So, now if I come to the that P n junction diagram and tell you about which particle will go where you should be able to understand various values for the coefficient you know both all of these are very important mobility and diffusion coefficient are very important are the material property they are dependent on the material that you are using they are dependent on the process that you are doing that they are dependent on the deposition technique that you are using there are so many various ways in which this particle can be dependent. One other important factor that is we do not go in detail, but as I told you yesterday that if whenever you draw the energy band diagram if you do you are not drawing the horizontal lines which means there is an electric field ok. As long as there is horizontal line there is no electric field whenever there is no electric field there is a whenever the bands are not flat it means that there is electric field and we can prove that right. We always know that expression for the electric field is gradient of the voltage that is electric field in the negative direction and you put this expression here you can find out that whenever there is a gradient this also means the gradient of voltage also means gradient in potential energy E is energy here. So, whenever there is a gradient in the potential energy means that there is electric field and what is this axis by the way always energy right. So, the line is not flat means there is a gradient in energy what energy potential energy which is given by E right because my y axis is energy and because this lines are not flat which actually indicates there is a gradient and the gradient actually means electric field that is the message I want to give right. In any band diagram whenever you see in your life from today onwards and whenever lines are not flat it indicates electric field ok. Now, if your drawing is very bad you may have a lot of electric field in your drawings, but make sure that you draw horizontal line because it makes lot of difference it makes it is very important point and it can play a huge role in making your device work or not work or you are actually improve the performance and lot of people actually play with this. So, this is another skill one should have to draw the appropriate energy band diagram. If you can draw it properly you know exactly how your device is going to work draw the appropriate energy band diagram ok. So, key thing from here is whenever line is not flat it means there is an electric field that is it ok and why it is not there it is because of this simple. Electric field is gradient in potential this is my potential energy axis because there is a gradient it actually indicates electric field ok. Einstein has found out that the two most important parameters that we have seen one is corresponding to the drift that is mobility other is corresponding to the diffusion that is D diffusion coefficient are related to each other. Yes, they are related to each other again we will not go to in the details of the expression how we have derived, but what is more important is the D and mu are related with KT by K. The more important thing is this is only depends on the temperature it does not depend on any material parameter. So, ratio of D or mu does not depend on any other third material parameter it is only depend on temperature. So, D by mu is equal to KT by Q is called Einstein relationship K is Boltzmann constant T is temperature Q is charge on the electron if you put the values there for a room temperature you will find this expression is equal to 25.6 25.9 25.9 close to 26 milli electron volt ok, you will find that value to be 25.9 milli electron volt. No it is milli volt milli volt this is centimeters square per second this is centimeter square per volt second everything will get as a milli volt and only KT is electron volt. If you only expression KT then it is energy unit of energy KT by Q is unit of volt only KT is unit of energy. So, if you are looking only KT then it is 25.9 milli electron volt KT by Q is 25.9 milli volt that is the value of that expression. So, D and mu are related with that I think should be true from this expression also if you divide mu KT by Q D by mu KT by Q you should find the similar relationship D by mu Dn by mu N KT by Q Dp by mu Q KT by Q should be the same.


The humanitarian situation in South Sudan is very difficult for the people. The pictures you are looking at were taken in a place called Minqaman in Lake State, about 150 kilometers north from Juba. This is a very good example of what hundreds of thousands of South Sudanese people are undergoing right now. People who were forced to flee their homes because of the violence, taking whatever they could manage to bring with them from clothes to mattresses or mosquito nets in some cases. I remember having talked to an old lady about 70 years old who was extremely worried about her her grandchildren, about 20 of them around her and she said something that really touched me a lot, which was that every afternoon she would drink goat milk and that now she didn't have that and she was left with nothing. Violence took away from her the little comfort she had in her life and probably she does not even realize that her survival prospects are being reduced by the day with this situation. The living conditions in the settlements for the displaced people are extremely harsh. They are living in the open air, you can have 45 Celsius during the day and it reduces by 20 or 25 degrees during the night. I remember having seen many families, old people, women and extremely many many many children all ages from babies to 10, 12, 14 years old boys and girls and I remember seeing these children actually playing with cars they made out of bottles and tops. Playing like regular children would play anywhere and this just reminded me of how in such an extreme situation in which they are lacking every single thing they still were trying to get a sense of normality as children do. From the beginning of the violence the ICRC started trying to help these people providing them with food, with water in some very creative ways. There are places where the water is directly being pumped out of the Nile for example, trying to reach areas by bicycle, by helicopter under very harsh and difficult logistical conditions in the approaching of the rainy season. The ICRC is deploying huge logistical efforts through planes, moving a lot of resources, human and material, trying to reach the people they need. The health infrastructure in South Sudan already before the conflict was very basic and almost insufficient to provide services to most of people. The violence affected this either because the medical infrastructure was destroyed or because the medical personnel themselves became displaced people or because people were afraid just to look for medical services afraid of the violence. The ICRC has deployed mobile surgical teams providing specialized surgical assistance to people wounded by weapons and this reminds us of the importance in a conflict like this to protect and to respect the civilian population as well as the medical infrastructure and the medical personnel that are there to help these people.


The Navy's latest career retention survey launches July 1st. Through the Career Viewpoint Survey and studies, sailors can provide feedback to help Navy leadership understand why and how they make career decisions and evaluate the effectiveness of Navy policies. These web-based surveys are voluntary and completely confidential. To find out how you can take the survey, visit the Chief of Naval Personnel's website. The Navy Exchange Service Command announced a $51.9 million donation to Navy Morale Welfare and Recreation, or MWR. Sailors and their families can save money when shopping at the Navy Exchange, and the money they spend ultimately improves their own quality of life. MWR can repair or construct new recreational facilities with the donated and sailor-generated money. Installations also receive a portion of the funds to increase command-level MWR efforts. Read more about these stories at navy.mil. From all hands, update, thanks for watching.


Going on everyone Sam here at late sports cards ripping 23 prism hobby and 22 select football hobby To box mixer number two random team style Look again at your random results as always you can find these on the website under the results tab as well as the link in Chat Billy F. Niners Charlie P. Seahawks up top Matthew L. Giants and Andrew B with the Browns on the bottom Good luck. Here we go. Let's start with select Anywhere but New England exactly I play space invaders Devon white to 149 pretty cool one here for the Bears Willie galt on the SuperBolotta Rats on that one and Fred Warner Zappy Silver their car frogger So he said they did was just play golf and chill Who Bofa? Oh, yeah drum for two 99 nerds So cool and Damian Pierce rookie Just I know I'm all too Terry kill we got a redemption of Bree's Hall rookie signature memorabilia prism going to the Jets nice one there in New York last fun digs to 99 Avis mill silver and Chris Olavi Just won't play my Atari Kenneth Walker Nick Bonita Probably we I don't we to 75 Jamal Williams. We was a we have one too. It's one there played it like four times I Like They've got Deandre Hopkins silver to Sean Watson and base who in chat thinks the we is fun everybody Everybody's gonna say yes, and sometimes Nathan not usually. I'm kind of used to it now gave on Tim it up sweet level It's opening packs here Sweet level. Yeah Quan brisker the Bears to 249 Baker silver for the Rams and can makers See, thank you Dave Dave knows Dave knows the Nintendo. We is fun. It is Traylon Burke silver Herbie David Montgomery exactly We I did both big win. Yeah for UCF. Yeah, so nice. Oh nice huge win Jerome Ford purple to 75 I Do finger crunches silver Kenny pick it and James Conner Storm in the court.  They should See Nathan says the Nintendo. We is the best. See you're in the minority When you get on one you're freaking funny.  He's not that we're shite Not that funny You know I'm saying I don't talk much. I do love. I love to get him going though That is like that is like my what I exist to do is don't do it on up, bro Fire it up in here Silver T-Law blue wave to 199 Vita Vaya Just in shorter and Jordan Addison rookie silver Andy Dalton Chris Godwin orange to 249 what up Nick Ozzie Smith and Tana Mickey. Hello Nick Nick, what's the weather where you're at right now? Where's Nick Minnesota, Nick are you one minute soda up there, Mike Alstott to 175 Clayton Tune and Aiden O'Connell rookie. I'll tell you my sister got 17 inches. I was at Mass. Yeah. Oh my god. I forget that There's a break tomorrow chase Evan Holt to 249 for the Colts Chris Rodriguez, Jr. And DeWon Johnson is riveting. Oh Blue wave Jordan Addison look at that shite back-to-back boxes with a baddison color to 199 Darnell Washington and tanked out congrats Vikings on that one Fred Taylor to 149 for the Jags Silverado nice one there. They're laughing Will Pevis Silver rookie Tana McKee purple 125 is Trey Hendrickson the bangles Roshan Johnson and Keon White. Don't you play Madden? Yeah Yeah, you have to have him stream that for sure That's Kenneth Walker Blue ice is Odell Beckham for the Ravens Byron Young and Darnell right with some out Thursday. Yeah. Oh, yeah, sir. Yeah, blue ice JSN for the Seahawks Yeah, you do Austin Hooper to 249 Probably I'd imagine yeah, you could probably just I don't know to be honest. I would just look it up but probably Silver Derrick Forrest, Jr. One of 25 Brandon Iook may be Camo Otto for the Niners Brian Branch and Breary Jones going to puke Is this a Uncharted territory he's watching his hands It's probably the first time it's like taking a bathroom. I don't think I've ever seen this.  It's got a backwards Michael Parsons That is Jacoby Myers to at 175. I need to talk to mr. Lester, please There's Davis and Dorian Williams Frank. That's Frank Lester on the phone Iook is Iook is awesome Jacob Struvon curse for the Titans to 149 Anthony Richardson rookie and a BJ Ojalare Quick recap here everybody pretty solid break over all we had Jamal Williams on the Jersey car autos of Brad and I it's 25 Fred Taylor Willie Galtz and Bresaul Do it for it the break everybody. Thanks again for the fill up next is a prism three boxer


Wonderful. Thank you so much Rachel for shepherding us through this and welcome everyone and thank you so much for joining us this afternoon for growing open education programs through a social justice lens. I know that you'll will all learn a lot here today from these amazing folks. So without further ado I want to go ahead and do introductions and then we'll get into the panel. So I'm in a daily the director of the Community College Consortium for we are at open education global, and I am your moderator today. We have four amazing open education leaders here. They're not only leaders on their campus and they all are have unique roles from each other, but they're also leaders within the open education community more broadly. So you're going to learn a lot today, and I will as well. All right, we will start with with Beatrice. Hi, I'm Beatrice Canales. I am a Senator college academic staff and open advocate slash practitioner in San Antonio, Texas. I am committed to being a unicorn in this field. And Senator college is one of the five colleges in the animal community college district. Thank you so much Beatrice. All right, Olivia. Good afternoon. My name is Olivia Chang. I'm professor at Manchester Community College here in Manchester Connecticut in one of my classrooms right now. I teach art history. And I'm also the project director of an NIH funded grant called not sure grandfather's art history. It's a collaboration with smart history. Some of you may know smart history is a platform of the Khan Academy. And so I have the honor of working with 23 different authors from across the country actually globally on that project so looking forward to sharing that with with all of you. Thanks so much. Thank you Olivia. Kate, you're up next. Hi everybody. My name is Kate Cameron. I am the digital services librarian at Kirkwood Community College which is our main campuses in Cedar Rapids Iowa. I've been supporting faculty adoption of we are here for about 10 years when I first took the CCC or training. Just to give you a little background Kirkwood has around 17,000 students and we're the second largest community college in Iowa. And as far as we are adoptions just to give you a brief kind of overview of where we are. We had basically pretty good supportive we are it's been kind of the tortoise rather than the hair I guess with kind of incremental adoptions over time, which is great they kind of build on each other. And I was really surprised to learn when there was a statewide we are survey that Kirkwood actually had the most we are adoptions of any college in Iowa. So that was, that was pretty awesome. And I'm looking forward to talking with everybody here today. Thanks Kate not I'm not surprised I've known Kate for a decade to I'm not surprised they're number one in Iowa. All right, last but certainly not least Joyce you may. Hey, everyone. My name is Joyce you mate. I'm the director of online education at College of the canyons we're located in Southern California, just north of Los Angeles. And at our college in our district. All of our work sort of lives under the online education department so I oversee a small team of current and former students who work with our instructors to help them. And also create we are on our campus. And in addition to to that work. I'm grateful to serve on the Executive Council of CCC we are and have had a whole lot of fun on another project open for anti racism project which I'll speak more about in this session but I'm really excited about that project because it's exploring how open education can be leveraged to make our teaching and learning anti racist so really thrilled to be here with all of you and with this incredible panel. Thank you joy and I have the pleasure of working with joy on a number of projects. I have a few of you who aren't familiar with the Community College Consortium for our community practice, supporting and encouraging colleges and collaborative development of open educational programs to ensure equitable and inclusive access and success. Really goals from 15 years ago when we were founded. It looks a little different these days you know things have changed in the last 15 years but we have always been all about equitable and inclusive access. And we are thrilled to have members across the country and in Canada as well. I just briefly, since this is a session on social justice I did want to mention that CCC OER has a strategic plan pillar number one which is on equitable learning speaks directly to social justice. I'm not going to read this to you but it's about including diverse learners and educators who've been underrepresented and more broadly bringing voices into the classroom into the educational materials of those who've been underrepresented and traditionally marginalized. So, just a little bit about some of the activities that we plan we have monthly webinars we have a group of folks on our exec council that do the planning around that based on surveys with our membership. And those webinars are open to all. If you join our community email there's a link there at the top of the page CCC OER or community dash email. You can join our email list and you'll get a notification of those events that are coming up and we welcome we welcome all interested educators. There's case studies available on our website as well not only from colleges who are engaged in OER work but also from students, and we also welcome guest blogs. We also have an equity book club that has a run for two summers in a row run by our equity committee. Joy mentioned the open for anti racism program. We're happy to co lead that with College of the canyons in the California Community College system. We also have a project called regional leaders for open education, which is run by Dr Karen Cangelo see and she just had a presentation she and her team earlier today. So today's topic. Community colleges were the hardest hit sector of public higher education during the pandemic. And the pandemic really exposed existing but we're seeing inequities and healthcare housing and schooling. And we know students lives were very disrupted but many colleges made efforts to keep their students engaged and enrolled at school and. Often one of the tools we are an open pedagogy to keep their students progressing on their academic plans. So it's so exciting to have panelists here from across the country as you know we've got, we've got California we've got Connecticut we've got Texas and we've got Iowa, and each and each of these panelists have unique roles that they play so I think there's something for everyone here. So we're hoping that what you'll learn you might be able to apply at your college depending on what your role is and you'll have an opportunity also to ask questions of these panelists. At the end but in the meanwhile please do post comments or questions in the chat as we go along. We'd love to answer those either if we can in the chat or at the end. Alright, so here are the panel questions that we're going to, we're going to start out with before we open it up to the audience. So our first one is tell us a little bit about the open education at your college, and also your own, but how did that pan, how did the pandemic change your open education focus. So a little bit about, you know, the journey and then the changes over the last couple of years. And then our second question is how does your campus center students and faculty from traditionally marginalized communities through your open education programs. And finally, what supports do you need to sustain and grow the open education programs focus on social justice. I am going to stop sharing now if that is okay with folks and so that you can see our panelists a little bit up closer. And so I'm going to start first with Beatrice and so tell us a little bit about your journey, both yours and at your college Beatrice and how did the pandemic change that. So, starting with the fall of 2020. I wanted to learn more about we are I saw that there was information at our college. And I, even though I went through masters of library science in 2019. I didn't really hear from my program about open education was very little. I took the Texas learns, oh, we are through digit tax. And I know it's growing and it's also, I think Oklahoma has a version of it and, and I discovered a whole field that I knew very little of and I attended my first open education conference which I never heard of. And it was online and I received a scholarship, and that led me to feel that I needed more education and experiences. So, you know, I've received my background is now, you know, the creative comments licensing. Yay, creative comments, which led me to feeling that I needed more. And I had a lot of experience and that led me to spark the open education leadership program. But, but prior to the pandemic, Senator colleges, we are work was entrusted by a task force of faculty librarians and college administration. The first Community College in Texas to win the prestigious 2021 Aspen Prize, our group knew that we needed to grow more education programs with a social justice lens. This past spring, the task force included a student representative and graduating student Victoria Villos from SGA. This practice to include student voices that share as shared governance. And colleague Lori Coleman said that our team should transition from open education awareness to open education action. Victor. So, Victoria's goals included co creating a campus white survey, because she felt that students from SAC with the data showing that the majority are female Hispanics, attending SAC part time, had enough intersectionalities that needed to be fully representative through survey gathering. My experiences outside of SAC and inside of SAC with students is the heart of social justice. I feel like I ended here but that's, that's how I understood that the question. Yeah, that's, that's wonderful to hear. And it's, it sounds like over the last few years as San Antonio has been also going through the pandemic along with all of the rest of us that students have gotten more involved. And they're gathering information now, which I think can be very valuable in terms of sharing that with your administrators, when they hear directly from the students. That's wonderful to hear. All right. And thank you for that question, Elena. I'm going to have to ask Beatrice to see if she can look that link up for you. I'll screw up the screen if I do that. And next up, Olivia, and would you like me to ask the question again or you all you're okay. Thanks, Una. Yeah, I've done some some of the key points there. Just quick question. Any, any people here who teach art history or her use art, often in their classes, humanities history. Okay, cool. So, personally, so I always taught art history I've been very lucky that I got my professional start in the community college system right at a grad school and it's really been, you know, it really speaks to I think, what I love about teaching is introducing students, you know, to really this whole world of history. And so it's been about 1011 years now. And in that journey, you know, I started fresh out of grad school told okay you got to teach the survey courses right so when you're in grad school you get very specific and you know your diet drilling down to these really nitty gritty details and then you're able to teach the survey class which is really everything from pre history to, you know, the modern period and so I, my first thing I did was turn to a textbook right the textbook I had been taught with in undergrad. And that worked for a while, and then I just got to the point where I couldn't teach that way anymore. One, my students had expressed that textbook textbooks were unaffordable for them. And our students are housing insecure food insecure so to buy an art history textbook, or even to rent one was just not feasible and and the lack of representation was also a key issue why I moved away from using a text. So actually I applied for a sabbatical one semester sabbatical and my college supported it which was great and it gave me that time and that space to explore what might be out there in terms of OER is for art history, and to really evaluate the best ones, and really to create one. So that was sort of beginning of the journey and that actually coincided with the pandemic. So all this kind of came to a head. And I, I so I did my research and I found that smart history was a great resource. It's designed for early college students for second year students introductory learners. It had videos it had short articles it had webinars it had just a whole variety of media. And so my idea started to generate of collective or creating a collection of essays that were authored by BIPOC scholars or scholars who identify as BIPOC. So that not only were we making this material accessible. But also diversifying the voices that were being included in the interpretation of objects and the narratives and the histories and the objects themselves right art history is a very traditionally Eurocentric field of study. And part of it it's just been a very organic process. One of the things I realized too is that I wanted equitable pay to be a part of this project I didn't want to ask scholars to just contribute their time and energy and expertise for free. I didn't want this to be a voluntary thing and I feel like also that's something that, you know, communities of color have been asked to do, you know, without being properly compensated so I applied for an NIH grant that was was a specifically community college fund. And so again my college was really supportive of that which I'm very grateful for. And so we're able to compensate our authors for their essays to this project. And in terms of the pandemic. Um, you know, I think it's, I think it's just exacerbated or shown us even to a greater degree, you know how access is so important, you know, to my students, you know they do their work on their phone, right so they don't necessarily have their own laptops their own computers so you, you need to be just mindful of that and the types of materials you choose right are they compatible with devices, you know that or computers let's say. And so I can't say that the pandemic sort of changed anything I was doing but I think it just like really threw it into a starker contrast of like how how pressing it is to keep doing the work that we're doing and that the whole culture of higher education is changed and is changing, and that you know the maybe how we were taught when we were in college is not is is perhaps not the best way to go forward so I think those are just sort of my final thoughts on things. And thanks Beatrice for your background as well so I'll pass it off back to you.  I'm sorry, the lawn blower came in the middle of that I didn't want everyone to hear that. So Kate. Tell us a little bit about your journey and how the pandemic change things at Kirkwood. Sure. So I guess I kind of jumped ahead in my introduction I talked a little bit about history of we are Kirkwood. As far as the pandemic. I really, I was very curious right away because I was hearing. We were fielding a lot of questions that first spring 2020 semester. Once everyone was home in March. I had lots of questions about like fair use and copying and scanning things and uploading them to the LMS and all those kinds of questions. And of course I took the opportunity to say you know there are these, you know, things called we are and there's open licensing and you know took that opportunity to to. You know, more faculty know that that was an option. And that they didn't have to, I still faculty, you know, it's so much easier if you just find the open license stuff. We don't even have to look at this, you know, fair use. Until then I noticed, yeah, almost right as soon as the semester was over in spring over that summer and into the fall. I just got so many people who wanted to learn about we are and I did a just in our course management system I did a little, you know, professional development course for faculty and yeah, by far the most participation there of any time I've done it that summer of 2020.  It always seems to just kind of be the slow and steady here but it definitely, you know, see that pattern of once one faculty and one department adopts, then I get, you know, over the next semesters, you know, more faculty from that same department are teaching that same course also get interested and kind of see, you know, that modeling of, you know, I, you can really do it and this is what it might look like and, you know, seeing faculty to and talking to them about how they're always, you know, they're constantly kind of updating materials and kind of adding things and leaving other things out.  And yeah, as far as pandemic change I think I just against it was sort of like it all of a sudden made sense for a lot of faculty like oh I can see now why, why, you know, why, why we are really kind of clicked for them, and they could see their students struggling I mean we had so many students that we were checking out lots of laptops, but also had to hurry up and try to find funding for hotspots just so so many students I see a brain on it yes. That did not that depended on being able to come to campus to get their internet access so that was a big push as well that what gosh that was probably the biggest, you know, difference that 2020 was just okay we have these materials that are open students can do what they need to with them they can print them download them, whatever they need to do. So yeah, that's kind of, that's kind of how it went for us. I've certainly you know in doing surveys across our membership we have heard that to that interest has grown. 2020 was a little crazy but after that I think it really sunk in that it was a digital era for those who had been kind of waiting to go digital. They unfortunately are fortunately depending on your perspective we're forced to go digital neighbors like Oh, oh I guess like I can do this. And joy is going to tell us about that because she's the online education director and she took her faculty through that. Yes. Well yeah I'm happy to share a little bit about kind of where our college was prior to the pandemic and what has shifted as a result of the pandemic. I've got a preface that I'm very fortunate I've been at College of the canyons for a little over six years now. And, you know, prior to my arriving at the college, we, and this is thanks to the leadership of my Dean James Glopper-Groes-Glag. Really, our campus had already pretty well established OER in terms of understanding first of all what OER even is, and embracing it as a, you know, a viable tool and resource to use for teaching and learning. But of course, you know, it was entirely optional for instructors to choose to use but our model on our campus prior to the pandemic. We spent a lot of time and really probably in the last five or six years spent a lot of time developing a team of current and former College of the canyons students to be that support system for instructors. Our focus on our campus was really like OER creation. We didn't place as much emphasis on adoption but really on creation. So the idea was that our team of current and former students could assist and support our faculty with, you know, all things OER that maybe was a bit outside of their wheelhouse. So we really wanted to be able to leave it to our instructors to be the content experts and then have a team that could offer the support like searching, formatting, you know, accessibility. And, you know, as Olivia said that this, it requires a lot of work that also requires and should be honored with compensation. In addition to compensating our instructors, we also just wanted to try to take as much of a load off of them by really trying to provide as much wraparound support with OER and really kind of like open textbook creation. And, you know, also our focus kind of pre-pandemic was really a big focus on cost saving. So a lot of the, as we would try to engage with faculty and encourage them to consider adopting OER, the pitch was always very much focused on cost and saving students, you know, reducing textbook costs. So I would say after the pandemic and as we were moving through and having to adjust through the pandemic. Obviously, all of us were teaching and learning online or some version of that and that in and of itself was a huge challenge and a huge lift, you know, providing that professional development support for our instructors so that they felt prepared and able to deliver quality instruction. And that also caused us as a campus and, you know, me as a leader on my campus overseeing OER to really consider what is it that, how can OER actually support our students and how can this be a resource for our instructors who are making this incredible shift online through the pandemic. So we kind of shifted our focus as it related to OER to really encourage more adoption. So as to lighten the load for our instructors, they were already, you know, making this huge shift to online. And so we didn't want to ask one more thing of them like, oh yes and write a textbook while you're at it, even though that had been our model and we still maintained our team. But that's a lot to ask when, you know, I know all of you were going through such an incredible transition. So we really shifted our focus towards adoption, but also recognizing some of the maybe existing limitations of OER but the opportunities that OER created to build and create virtually responsive materials. So it was an opportunity for us to sort of shift our pitch to our instructors about this is an opportunity for us to work in partnership to, you know, adopt and adapt existing materials but also you can contribute to our expertise while elevating the contributions of others in the field, you know, BIPOC contributors to the field, which was really important. So, you know, that shift towards adoption also was a shift towards us, not only making the pitch about cost but making the pitch about how this is an opportunity for our students to see themselves in their learning. This is an opportunity for our students to also have, you know, provide better access to the learning materials. But also in my role on campus, I am an administrator so you know we're all kind of dealing with the challenges of declines in enrollment and it enabled us to help make the pitch for OER being utilized or leveraged as an enrollment management strategy. So we look very heavily to and we work in close partnership with our institutional research team on campus because data. Data will make the case when we're trying to find funding, you know, and, you know, again back to Olivia saying, you know, we have to be able to pay our instructors for this incredible work that they're putting in. So to make the case, you know, turning to data has been something that we have really relied heavily on because the data supports that OER helps our students. So we look at everything from success in retention rates, which locally on our campus, we have the local data to show that students are succeeding at a higher rate in courses that are using OER. We have the data from our institutional research team to show that we're retaining students and OER classes. And, you know, in terms of enrollments, you know, we have, we look at fill rates, so those are the rate at which courses reach full capacity, and we have the data over time to show that, you know, courses that are scheduled that appear as OER or zero costs, but cost in the schedule of classes, those fill and those outpace the fill rates of classes that don't use OER. So, you know, it's kind of trying to meet the needs, like show how OER can meet the needs of our campus community. And being able to kind of shift the conversation based on who you're talking to or who you're maybe reaching out to for resources. So building those connections with instructors and appealing to them in a way that's meaningful to them in terms of, you know, the opportunity to include students and help your students succeed, but also being able to, you know, have a strong argument or a strong case, maybe when, you know, trying to convince other administrators, like, yes, we need to keep funding these projects. So the pandemic has very much shifted our focus, but I would say sort of the silver lining out of it is I think we've shifted in a positive way that is proving to be more helpful for our students. Thank you, Joy. It is important. I want to circle back around to Beatrice because I don't think she shared her very special project that she led at through her Spark leadership program and she's implementing on her campus. Yes. So, in my Spark Open Education Leadership Fellowship, I focused on international and or dual citizenship students. There are also unicorns on our campus and I felt that they would have a unique point of view on how to create content with a bilingual and or by cultural lens. I paired a works, for instance, I paired a work study student Allison with a faculty member that adopted the students renewable assignment resource because through their collaboration, they produced a wonderful resource that will increase more diverse student voices every semester. Allison had a dual citizenship in Mexico in the US, but she had to pay out of pocket for her classes. So back to compensation. I wanted to be able to offer Allison a way for her to find meaning and have something for her to receive at the end of her work with us. So, not only did she add her openly licensed resource link to her resume and portfolio. She also received experiential credit through Alamo colleges, because through her reflection on San Antonio colleges marketable skills rubric and her own self reflection on the whole process. Also, Allison and I, we agreed that her OER work utilize many of the skills necessary marketable skills, necessary for her to receive this credit on a transcript. We agreed that she utilize her communication her critical thinking, social responsibility or global engagement and personal responsibility skills. The OER and marketable skills work that she did that Allison did. She was able to view her work, her lens to exist after she graduated. And do this work I wanted to make sure that open pedagogy is around on our campus. And this was something that I knew that if we would tap into our students to look at their open work as not only for what they can do at the college but for themselves for the global community. Then I, I wanted to make sure that she felt engaged and also was able to be compensated for her time. And so, together I think this was a great way for her to enhance her learning and it was a way for the faculty member to adopt a resource that that she had never heard of, which was a renewable assignment and she was able to adopt that and add to her curriculum and she said this will help her. The faculty member was able to look at her curriculum in a different way and and to add more meaning for students who would take her courses. Thank you Beatrice and that's a wonderful example of open pedagogy and service learning, intersecting along with aligning with, you know, learning outcomes for your college around marketable skills because that's all of us are trying to do that our colleges is to help students develop marketable skills so that they can go out in the workplace as they complete their degrees and really take all that forward so that's very encouraging. I'm doing a little check on the time. I have like, we have kind of like one question left and I'm going to give it as kind of an option if you want to answer it. And then we will move to audience to the audience participation I know we have at least one or two questions in there that have been that have been posted. So, all of you are focusing on social justice in some aspect at your college through the lens of open education we are open pedagogy open educational practices. What supports do you need to sustain and grow that work because you know, a number of you had mentioned when we did our little rehearsal that you'd used her funds. So you'd use some of the pandemic recovery funds to to to up your OER efforts during the pandemic but those of course will go away. If they haven't already. If you haven't already spent those and so what what do you need and I know that funding is always the top one but if you can be a little more nuanced about besides funding what other kind of supports do you need at your campus and I'm going to raise your hand or you can just speak up panelists, whichever whoever would like to go first. I'm happy to go for it. Well yes, as you mentioned, of course, you know, time energy and money we can never have enough of those things to support this effort. I think that'll be on the top of most of our lists for forever moving forward. But beyond beyond that. I would say, you know, some professional development training has proven very important and really essential, especially as we embrace approaching OER and open pedagogy with a particularly with a culturally responsive lens. And also offering our, our faculty that that professional development support, and then also sort of following the model that we develop locally on campus, ensuring that we're able to continue providing support to a team who can then offer the support to our instructors. So, you know, I would add that partnerships on campus are incredibly valuable to sustain the OER efforts or open efforts on your campus. And also to, to, to grow and enhance those efforts as they relate to ensuring that we're approaching this work equitably and to meet the needs of our students. One of the ways that we do that on on campus is partnering partnering with our academic senate and our associated student government. When you have buy in from from those groups that alone for us has been really instrumental and helpful. And, you know, I go back to what Kate mentioned like that helps us sort of open the door to have a conversation for maybe one instructor to consider adopting OER or even creating their own. And that opens the door even wider to maybe an entire department or a group of instructors who teach the same course, kind of embracing that resource, and then recognizing their opportunities to perhaps adopt or create even more. But also, you know, partnerships, a lot of, I would imagine a lot of your campuses are really engaged in, you know, equity work or, you know, whatever terminology that you're using on your campus and you know inclusion work. So partnering with those groups on campus can be really valuable because, you know, again, it's our approach is less about, you know, teaching to the textbook but rather open being a tool that can be leveraged for teaching and learning. So partnering with those groups on campus who are having these conversations so that we are or your open work doesn't just exist in a silo but rather is viewed as a tool and an opportunity in those equity conversations or in those enrollment strategy and management meetings. You know, folks on our campus might be a little bit tired of hearing me but trying to have a seat at the table by showing up and saying like hey, OER and open pedagogy is a tool for this thing you're trying to accomplish here on campus. So instead of it kind of living in its own little silo, you know, for me and for us on our campus really trying to leverage open as a tool to help our campus meet a variety of needs. That's so important. Thank you, Joy. Yeah, those partnerships are really key. And I think I saw Olivia first. So I'll go to Olivia. I just wanted to echo exactly what Joy was saying and just say that, you know, it can be an intimidating prospect I think to, you know, to shift away from a text or the way you've been teaching for so long and to embrace something new and maybe entirely digital. And I think that is really key is like building the sense of community, whether it's at your campus or across campuses within your discipline that I think it's also really important to like give instructors the sense of, you know, this allows them flexibility to learn, but they're also part of a larger conversation that you said, Joy, and that, you know, their support beyond just like here's, you know, here are these materials like go forth with them, you know, that you can as an instructor, you know, learn through this process and that it takes time to adjust and figure out what works best for you. And that, you know, you're not the only one making this transition and then maybe you can learn from others and their experience. So yeah, I think, you know, when we go into teach sometimes we are very much in like our own little silos and so I think it's really valuable to join a community if there's not one established already, or just, you know, know that, yeah, there are others, you know, out there and to join a community if you can, or to see if you can build one of people, you know, experiencing the same thing. Beatrice, go ahead, sir. Just a quick. I put down data mining for how faculty utilize open pedagogy, because the Alamo colleges we have a OER attribute for all of our OER and inclusive access attributes. And so we can easily find, you know, which courses are utilizing OER, but we're not capturing those faculty that uses open pedagogy, but do not have a full course. Revolving around it. So I believe that, you know, going forward, you know, that data that includes faculty who utilizes some part of open in their classrooms should also be celebrated. At that sector, we're going to have a student vote on the best OER that is submitted by faculty. So we have faculty who are submitted the best OER sites and students are voting on what they consider as the best of all the faculty. So it's really SAC trying to find ways to find the faculty who are using open pedagogy, but are not putting down on that attribute that they're an OER course. And it's students using their right to vote and find the best, how they see is the best resource for their own learning and education at SAC. Wonderful. I mean, that that'll help create awareness, I think, around OER, having the students vote. I mean, both ways, right? Faculty will be competing a little bit and students will be voting. So wonderful idea. Well, I think at this point, Kate, would you, did you, you're okay? Okay. So I think at this point, we will go to questions from the audience. We did have one way back, I think, maybe Rachel, Rachel might have caught some that I didn't as well. We had one way back about using your phone. So rather having developed making sure that OER is compatible with students' phones since we know that for the majority of students these days, the phone is the first thing that they use. And I don't know if one of our panelists would like to speak to that. Beatrice, did you want to speak to the phone?  Would somebody like to speak to that one? I don't really, I haven't run into it much, the question. We recently subscribed to Pressbooks. And that's, I think, one of the benefits of, you know, having a platform that has all those, I mean, there's so many file types that you can convert to, you know, with one, with just the one editing platform. You don't have to press, you know, Pressbooks in particular, but just as an example of that flexibility. But yeah, I don't have a lot of experience with that. I know that that's something very desirable. So thank you for whoever posted that. I don't know, Joy, if you have any experience with that. I mean, with your OER team, I know you test for accessibility. I don't know if you test on the phone at this point to make sure that is that. Yeah, we don't, I mean, we just format our text for accessibility more broadly. So I haven't actually, it's a great question, but it hasn't really come across sort of my desk, if you will. It hasn't been something that instructors have expressed is a challenge. I think, you know, just more broadly the access in general is a challenge for students. I think Olivia mentioned, you know, many students just not having access to even a laptop or desktop in the first place. But on the whole, you know, we've just seen that when we're designing and part of that is the course design, you know, online course design for the mobile experience so also shifting in emphasis towards that but as it relates to OER we haven't heard a lot of feedback and positive or negative as it relates to a mobile experience. But I would say in that case, the access in and of itself has has been a significant help for students. So, yeah, none of our survey data has has from students has come back to say that it's been problematic. Thank you, thank you for sharing that we had a question from Phoebe, which we might want to speak to so regarding professional development. Can you speak more about your approaches. I heard in recent session about folks moving forward toward one on one support versus creating a canvas course for example. So this is probably to joy and Kate who do a lot of professional development in their capacity and I'm sorry Beatrice and Olivia if you do as well please please feel free to address that question. It looks like Joy put a really good response there in the chat. Yeah, I missed it. I'll just jump in was kind of my approach is just I sort of approach it with what I learned about being a librarian which is, you have to be available when somebody has the question has the need. You have to talk about yourself all the time. You know if there's a professional development opportunity, you know offer something, even if it's not the best venue for maybe getting people started it gets the information out there and lets people kind of see oh, I'm not the only one interested and maybe I can work with my colleague over here and kind of building that. Great luck with online workshops I mentioned I offered one in 2020 that went pretty well. But people tend to need that one on one help. And then the other aspect of that is just knowing the other people in your college who can provide support. For example, sometimes the person finds faculty finds the OER but they really have some technical issues, or they're trying to integrate it with their assignments I say you know why don't you talk to Mike. He's an instructional designer he's going to be all over that you know so kind of being able to, you know work together in that way and pass the ball around without worrying you're dumping something here. Yeah, instructional designers rock we didn't we didn't get today but yeah on the panel that they definitely do. Wonderful. Yes, and I joys joys comments that were were quite appropriate that. And I think a combination with case is that you need to be there to answer the question but for some faculty they really do want to work asynchronously and it's certainly not all. You to answer a couple questions live but then they can go off and work asynchronously so I definitely think you've got to look at God forbid I should say learning styles of your faculty, you know and offer a variety. Were there any other questions we missed. But I missed. I knew we're at we got two minutes to go right Rachel. Yes, I did see one question in the chat about OER materials being provided and for profit kind of platforms. So I don't know if you would like to address that or not but I did see that mentioned in the chat. Yeah, yeah I did see that one too I mean open licensing that's, that's a possibility so stewardship is a really important consideration for the open ed community. I mentioned the care framework and thank you to divesta, our CCC OER exact Council President, who works at is me she posted the care framework, which talks about that. I don't know if anyone else has something more that they can add on that. I think it is unfortunate that some of the people who contributed to the Lumen learning courses didn't expect them to turn up there on course hero. It was quite a discussion on our email list about that. Six months ago, I think. Well, I want to thank these panelists. You know once again I learned more today from them and I thank our audience for joining us. I think we can hang around a little bit after Rachel turns off the recorder. If you've got some individual questions and I can stay here for another 10 minutes I'm not sure if my panelists can. Some of them teach and have other responsibilities. Thank you again.