defects diamond crystal diamond common defects diamond result irregularities introduced diamond growth defects affect material properties diamond determine type diamond assigned dramatic effects diamond color electrical explained band theory defects detected different types including electron resonance induced light electron beam absorption light infrared visible parts spectrum absorption spectrum identify defects estimate concentration distinguish natural synthetic enhanced diamonds labeling diamond centers tradition diamond label defect induced spectrum numbered acronym tradition followed general notable centers confusing symbols similar accidentally labels given different centers detected optical techniques center optical center relation logical natural observed natural diamond heated observed heating particular clear distinction meaning labels general radiation radiation type radiation defect symmetry symmetry defects crystals described point groups differ space groups describing symmetry crystals absence translations fewer number diamond defects following observed far defect symmetry allows predicting optical properties example infrared absorption pure diamond forbidden center introducing defect symmetrical pair breaks crystal symmetry resulting defect induced infrared absorption common tool measure defect concentrations diamond synthetic diamond grown high pressure high temperature synthesis chemical deposition defects symmetry lower align direction growth alignment observed unique diamond defects analyses diamond reveal wide range originate foreign materials diamond small invisible optical microscope virtually element diamond essential elements introduced diamond isolated small atomic clusters diamond growth elements nitrogen hydrogen detected diamond originate foreign detection isolated iron diamond later interpreted terms micro particles produced diamond synthesis oxygen believed major diamond identified diamond electron resonance centers assigned nitrogen oxygen complexes assignment indirect corresponding concentrations low parts million nitrogen common diamond nitrogen comprise diamond mass previously defects diamond thought result structural later research revealed nitrogen present diamonds different configurations nitrogen enters diamond single nitrogen containing molecules incorporation molecular nitrogen incorporates diamond absorption light material properties diamond highly dependent nitrogen content state aggregate configurations cause absorption infrared diamonds containing nitrogen usually little absorption visible spectrum main nitrogen forms follows nitrogen center center corresponds electrically neutral single nitrogen diamond easily seen electron resonance called centers centers deep yellow brown color diamonds classed type commonly known diamonds rare gem form synthetic diamonds produced high pressure high temperature technique contain high level nitrogen form nitrogen originates atmosphere source nitrogen carbon produce yellow color nitrogen available carbon replace act deep donors nitrogen extra electron donate forms donor energy level band gap light energy donor band resulting yellow color center produces characteristic infrared absorption spectrum sharp peak broader feature absorption peaks routinely measure concentration single nitrogen proposed way absorption later discarded unreliable defects diamond fifth nitrogen electron center converting center characteristic absorption spectrum sharp peak broader weaker peaks nitrogen center center probably common defect natural diamonds consists neutral nearest neighbor pair nitrogen carbon center produces absorption threshold invisible eye causes coloration diamond containing nitrogen predominantly form classed type center light deep produces electron resonance spectrum analysis proves structure center shows absorption spectrum sharp features distinctly different centers strongest peak routinely estimate nitrogen concentration form nitrogen center general consensus center called consists carbon vacancy surrounded nitrogen carbon model consistent experimental results direct data diamonds nitrogen forms centers rare classed type gem diamonds contain mixture centers centers similar centers centers induce color visible absorption attributed centers early assignment absorption system center later center characteristic absorption spectrum infrared absorption picture sharp peak broader feature routinely estimate nitrogen concentration form note optical peaks diamond accidentally similar positions causes confusion use defect identification spectrum peak consider history growth processing individual diamond nitrogen center center consists nitrogen surrounding vacancy concentration fraction centers center structure justified analysis spectrum defect produces characteristic absorption line induce color center accompanied center having absorption line result diamonds rich centers yellow color diamonds containing termed type percent natural diamonds type blue grey diamond available electron carbon carbon creates electron hole band gap accept electron band allows red light absorption small energy needed electron leave band holes released band room temperatures holes electric field render diamond electrically type required happen typical ratio carbon diamonds transmit light absorb red infrared light blue color blue exposure light apart optical absorption detected electron resonance intentionally introduced diamond grown chemical deposition concentrations carbon diamond similar nitrogen electron carbon acts donor energy smaller nitrogen small room temperature thermal important property diamond favors electronic applications light hydrogen hydrogen technological important including diamond hydrogen related defects different natural diamond synthetic diamond films films produced chemical deposition techniques atmosphere rich hydrogen typical hydrogen carbon ratio strong bombardment growing diamond result diamond rich hydrogen films hydrogen located boundaries diamond grains non diamond carbon diamond hydrogen vacancy hydrogen nitrogen vacancy complexes identified negative charge states electron resonance addition numerous hydrogen related absorption peaks documented demonstrated hydrogen electrically active result shallow donor centers presumably produced natural diamonds hydrogen related absorption peaks commonly observed strongest ones located absorption figure microscopic structure corresponding defects unknown certain defects originate diamond foreign gray color diamonds australia associated hydrogen defects assignment diamonds grown high pressure high temperature technique metals usually added growth medium facilitate conversion diamond result metallic formed isolated incorporate diamond demonstrated characteristic structure electron resonance optical absorption concentration isolated reach fact means unusual considering large difference size carbon transition metal superior diamond numerous related defects detected electron resonance optical absorption synthetic natural diamonds major structures distinguished vacancy vacancy complex decorated nitrogen vacancy structure called semi specific large diamond tin production mechanism generally accepted follows large incorporates nearby carbon creating neighboring vacancy shifts sites physical chemical properties similar concentrations isolated diamond smaller parts billion range defects related isolated detected electron resonance structure unknown common diamond films grown chemical deposition originates substrate windows walls observed natural diamonds dispersed form isolated defects detected diamond sharp optical absorption peak electron resonance similar large major form diamond identified vacancy complex semi site center deep donor having energy unsuitable electronic applications constitute minor fraction total believed proof exists carbon invisible techniques carbon configuration outer electronic shells normally absent diamond introduced growth subsequent diamond detected vacancy center similar properties vacancy center year wave attempts synthetic diamond films aiming type low activation energy successful reports published dismissed rendered type instead type associated highly efficient type diamond far reliable evidence interaction structure electron resonance isolated defects diamond corresponding center called observed natural type diamonds small concentrations parts million assigned vacancy complex case semi site defects easiest way produce defects diamond displacing carbon high energy particles alpha beta gamma particles etc occur laboratory nature diamond produces primary defects named defects carbon knocked normal sites sites remaining important difference diamond mobile liquid nitrogen temperatures start migrating temperatures produced diamond plastic smaller concentrations isolated carbon isolated observed diamond considered unstable interaction regular carbon produces split defect carbon share site carbon neighbors defect thoroughly characterized electron resonance center optical absorption unlike defects diamond produce complexes isolated split moves diamond crystal meets larger complexes split identified electron resonance centers optical absorption vacancy complexes high energy particles displacing carbon site pass surplus energy rapid migration relatively gentle gamma extra energy minimal remain near original form vacancy pairs identified optical absorption vacancy pairs produced electron different mechanism individual migrate aggregate form process occurs near isolated vacancy isolated vacancy studied defect diamond theoretically important practical property optical absorption like color centers gives diamond green green blue color pure diamond characteristic feature absorption series sharp lines called line prominent important vacancy deep electron donor electronic properties depend charge state energy level states states band complexes pure diamond migrate form characterized optical absorption electron resonance similar single produce turn creating chains detected presumably rings invisible detected far changes diamond color green yellow brown similar mechanism vacancy believed cause brown color deformed natural diamonds common structural defect natural diamond major types set bonds break layers different lying directly shuffle set breaks occur index produce bonds introduce energy levels band gap enabling absorption light blue reliably identified direct observation electron microscope noted type parameters natural diamonds contain extended defects planes called size ranges large ones easily observed optical microscope long time tentatively associated large nitrogen complexes nitrogen produced result nitrogen high temperatures diamond synthesis direct measurement nitrogen technique electron revealed little nitrogen currently accepted model large regular array carbon produce sharp absorption peaks absorption remarkably position peak depends size broad centered associated direct observation electron microscope studying sized clusters present natural diamonds revealed electron laboratory experiments demonstrated type diamond high temperatures pressures results break formation loops result thermal degradation contrary contain nitrogen molecular form interaction defects defects interact producing new defect complexes interaction usually occurs diamond containing defects deformed important interaction nitrogen carbon react nitrogen producing bond centered nitrogen showing strong absorption efficiently trapped nitrogen centers trapping rate highest centers times lower centers times lower centers center single nitrogen trapping vacancy forms famous nitrogen vacancy center neutral negatively charged negatively charged state potential applications quantum computing centers trapping vacancy create corresponding centers simply negatively charged center neutral center centers important present natural diamonds optical absorption strong alter diamond color yellow green carbon forming neutral complex sharp optical absorption evidence known far complexes vacancy contrast react creating described optical absorption assumed mechanism trapping migrating vacancy resulting semi configuration similar mechanism expected semi configurations reliably identified unpublished study diamonds rich electron following careful optical measurements performed step evidence creation vacancy centers obtained
Crystallographic defects in diamond