《电子陶瓷》教学课件

《电子陶瓷》幻灯片本课件PPT仅供大家学习使用学习完请自行删除，谢谢！本课件PPT仅供大家学习使用学习完请自行删除，谢谢！《电子陶瓷》幻灯片本课件PPT仅供大家学习使用ElectronsandHoles

InanintrinsicS.Mlikesiliconattemperaturesaboveabsolutezero,therewillbesomeelectronswhichareexcitedacrossthebandgapintoC.VandwhichcanproducecurrentWhentheelectroninpuresiliconcrossesthegap,itleavesbehindanelectronvacancyor"hole"intheregularsiliconlatticeUndertheinfluenceofanexternalvoltage,boththeelectronandtheholecanmoveacrossthematerialInann-typesemiconductor,thedopantcontributesextraelectrons,dramaticallyincreasingtheconductivityInap-typesemiconductor,thedopantproducesextravacanciesorholes,whichlikewiseincreasetheconductivityElectronsandHolesInanintrP-andN-typeS.MP-andN-typeS.MBandsforDopedSemiconductorsTheapplicationofbandtheoryton-typeandp-typesemiconductorsshowsthatextralevelshavebeenaddedbytheimpurities.Inn-typematerialthereareelectronenergylevelsnearthetopofthebandgapsothattheycanbeeasilyexcitedintotheconductionband.Inp-typematerial,extraholesinthebandgapallowexcitationofvalencebandelectrons,leavingmobileholesinthevalenceband.BandsforDopedSemiconductorsP-njunctionTheopencirclesontheleftsideofthejunctionaboverepresent"holes"ordeficienciesofelectronsinthelatticewhichcanactlikepositivechargecarriers.Thesolidcirclesontherightofthejunctionrepresenttheavailableelectronsfromthen-typedopant.Nearthejunction,electronsdiffuseacrosstocombinewithholes,creatinga"depletionregion".TheenergylevelsketchaboverightisawaytovisualizetheequilibriumconditionoftheP-Njunction.Theupwarddirectioninthediagramrepresentsincreasingelectronenergy.P-njunctionTheopencirclesCompletep-njunctionAp-njunctioninthermalequilibriumwithzerobiasvoltageapplied.Electronsandholesconcentrationaredrawnrespectivelywithblueandredlines.Grayregionsarechargeneutral.Lightredzoneispositivelycharged.Lightbluezoneisnegativelycharged.Theelectricfieldisshownonthebottom,theelectrostaticforcebuildingbetweenelectronsandholesandthedirectioninwhichthediffusiontendstomoveelectronsandholes.Completep-njunctionAp-njunDepletionRegionWhenap-njunctionisformed,someofthefreeelectronsinthen-regiondiffuseacrossthejunctionandcombinewithholestoformnegativeions.Insodoingtheyleavebehindpositiveionsatthedonorimpuritysites.

Depletionregionisanon-conductinglayerDepletionRegionWhenap-njuMoreDetailInthep-typeregionthereareholesfromtheacceptorimpuritiesandinthen-typeregionthereareextraelectronsWhenap-njunctionisformed,someoftheelectronsfromthen-regionwhichhavereachedtheconductionbandarefreetodiffuseacrossthejunctionandcombinewithholesFillingaholemakesanegativeionandleavesbehindapositiveiononthen-side.Aspacechargebuildsup,creatingadepletionregionwhichinhibitsanyfurtherelectrontransferunlessitishelpedbyputtingaforwardbiasonthejunction.RecombinationMoreDetailInthep-typeregiCurrentinS.MBothelectronsandholescontributetocurrentflowinanintrinsicsemiconductorThecurrentwhichwillflowinanintrinsicS.Mconsistsofbothelectronandholecurrent.Thatis,theelectronswhichhavebeenfreedfromtheirlatticepositionsintotheconductionbandcanmovethroughthematerialInaddition,otherelectronscanhopbetweenlatticepositionstofillthevacanciesleftbythefreedelectrons.Thisadditionalmechanismiscalledholeconductionbecauseitisasiftheholesaremigratingacrossthematerialinthedirectionoppositetothefreeelectronmovement.CurrentinS.MBothelectronsaBiaseffectonelectronsinD.Z:Equilibriumofjunction

Coulombforcefromionspreventsfurthermigrationacrossthep-njunction.electronswhichhadmigratedacrossfromtheNtoPregioninformingofdepletionlayerhavenowreachedequilibrium.OtherelectronsfromtheNregioncannotmigratebecausetheyarerepelledbythenegativeionsinthePregionandattractedbythepositiveionsintheNregionBiaseffectonelectronsinD.BiaseffectonelectronsinD.Z:ReverseBias

ConnectingtheP-typeregiontothenegativeterminalofthebatteryandtheN-typeregiontothepositiveterminal,producesthereverse-biaseffectAnappliedvoltagewiththeindicatedpolarityfurtherimpedestheflowofelectronsacrossthejunction.Forconductioninthedevice,electronsfromtheNregionmustmovetothejunctionandcombinewithholesinthePregion.Areversevoltagedrivestheelectronsawayfromthejunction,preventingconduction.

BiaseffectonelectronsinD.BiaseffectonelectronsinD.Z:ForwardBias

Forward-biasoccurswhentheP-typesemiconductormaterialisconnectedtothepositiveterminalofabatteryandtheN-typeS.Mmaterialisconnectedtothenegativeterminal,asshownbelowAnappliedvoltageintheforwarddirectionasindicatedassistselectronsinovercomingthecoulombbarrierofthespacechargeindepletionregion.Electronswillflowwithverysmallresistanceintheforwarddirection.Or,youcansaythedepletionregionbecomesnarrowenoughBiaseffectonelectronsinD.Bandstructureofp-njunctionBandstructureofp-njunctionI–VCharacteristicsApnjunctionisanon-lineardevice,a“valve〞withan“easy〞anda“difficult〞currentdirectionIthasanonvoltageandabreakdownvoltageIVpnVIBreakdownprocessesarenon-destructiveandarereversibleI–VCharacteristicsApnjuncIntroductionpnandnpdiodecurrent-voltagecharacteristicsVIVIpnVIVInpThesecurrentsdonotobeytheOhm’slawIntroductionpnandnpdiodecuSchottkybarrierstoconductionsSchottkybarrierstoconductioSchottkyBarrierVariousSchottkybarrierdiodes:Smallsignalrfdevices(left),mediumandhighpowerSchottkyrectifyingdiodes(middleandright)ASchottkydiodeisaspecialtypeofdiodewithaverylowforward-voltagedropSchottkyBarrierVariousSchottSchottkyDiodeASchottkydiodeconsistofametallayeronasemiconductorsubstrateAccordingtothesimpleSchottkytheory,thebarrierheightFBthatexistsatthemetal/semiconductorinterfaceisgivenbyTheelectronsmustflowoverthebarrierwhenthedeviceisbiased-knownasthermionicemissionFBineVfBinV;FB=-qfBFBorfB?!what’sgoingonhere?ECEVV=0fBVbiVSchottkyDiodeASchottkydiodeSchottlyDiodesEnergyband

diagramofthemetalandthesemiconductorbefore(a)andafter(b)contactismade

SchottlyDiodesEnergybanddiaSchottlyDiodesSchottlyDiodesSchottkyDiodeThecurrent-voltagebehaviorofaSchottkydiodeisgivenbyVonVBDIV(A:area;A*:RichardsonConstant)ECEVV=0fBVbiVIncreasingfBSchottkyDiodeThecurrent-voltSchottkyDiodeThecurrent-voltagebehaviorofaSchottkydiodeissimilartothatofapnjunctionECEVV=0fBVbiECEVV<0BarrierisfBVbi+VECEVV>0BarrierisVbi-VElectronflowSchottkyDiodeThecurrent-voltMetal-n-S.MContactTheenergyfmrequiredtoremoveanelectronwiththeFermienergytoapointoutsidethemetalwithzero.Whenelectronsarethermallyexcitedoutofasemiconductor,theeffectiveworkfunctionfsofthesemiconductoristheenergydifferencebetweentheFermienergyandthevacuumlevel.Metal-n-S.MContactTheenergyOhmicContactTheaimofanohmiccontactprovidethecurrentthatthedevicerequiresthevoltagedropacrossthecontactshouldbelessthanthevoltagedropacrossthedeviceTherearetwoimpedimentsforcurrentflow:thebarrierheightandthebarrierwidthItisalmostimpossibletochangethebarrierheight,butwecanchangethebarrierwidthWbyincreasingthedopingdensityND

ECEFEVWThermionicemission(overthebarrier)SchottkyDiodeECEFEVWFieldemission(tunneling)(throughthebarrier)OhmicContactOhmicContactTheaimofanohmOhmicContactI-VchangessubstantiallyasthebarrierwidthchangesASchottkydiodeturnsintoanohmiccontactIVOhmicContactNDincreasesSchottkyDiodeOhmicContactI-VchangessubstOhmicContactCompletebanddiagramofapnjunctionIhavenevereverseenanenergybanddiagramlikethisbefore!p+pnn+OhmicTunnelContactOhmicTunnelContactTunnelingTunnelingAnimportantpropertyofEfisthat,forasysteminthermalequilibrium,itisconstantthroughoutthesystem.OhmicContactCompletebanddiaApplicationsMetal-semiconductordevicesfindapplicationsas:NonlinearSchottkydiodesRectifiers(canvarytheonvoltage)Highfrequencydetectors(majoritycarrierdevices)Gatesofcertainfield-effecttransistors(metal-semiconductorFETs)OhmiccontactsOhmiccontactsApplicationsMetal-semiconductoSummaryForward-biasandreverse-biaspropertiesofthep-njunctionimplythatitcanbeusedasadiode.Ap-njunctiondiodeallowselectricchargestoflowinonedirection,butnotintheoppositedirection;negativecharges(electrons)caneasilyflowthroughthejunctionfromntopbutnotfromptonandthereverseistrueforholesWhenthep-njunctionisforward-biased,electricchargeflowsfreelyduetoreducedresistanceofthep-njunctionWhenthep-njunctionisreverse-biased,however,thejunctionbarrier(andthereforeresistance)becomesgreaterandchargeflowisminimal....SummarySemiconductivityinOxidesModelsforoxidessystemaremuchmorecomplexthanforsiliconbecauseofPurityLimitationinOxidesSemiconductivityinOxidesModeElectronic/IonicCompensationofSolidsInacovalentS.M,theeffectivenessofdonorsandacceptorsissolelydeterminedbytheirionizationenergiesInoxideS.M,theydependsontheextentofoxidationandreductionAnaliovalentsoluteinanioniccompoundcanbecharge-compensatedbyionicdefectsorbyelectrons/holes,ormixedcompensationLargevariationsinelectricalconductivitycanresultwithchangesinPO2andTataconstantdopinglevel,duetochangesinthecompensationmechanismNote:Thetermionizationenergyismostcommonlyusedtorefertotheenergyrequiredtoremove(toinfinity)theoutermostelectronintheatomormoleculewhenthegasatomormoleculeisisolatedinfreespaceandisinitsgroundelectronicstateElectronic/IonicCompensationExample:IncorporationofNb2O5intoTiO2IoniccompensationElectronicCompensationOxidation/reductionequilibriumAtlowerNbconcentrations/higherT./lowerO2pressure,whichisdominant?AthigherNbconcentrations/lowerT./higherO2pressure,whichisdominant?Example:IncorporationofNb2OSimultaneousDefectEquilibria:BrouwerDiagramDefectformationreactionsofinterestwillgenerallyincludethosePredominantintrinsicionicdefects(SchottkyorFrenkel)IntrinsicelectronicdefectsOxidationandreductionIncorporationofanysignificantsolutesorimpuritiesThesereactionswillinvolveatotalofNdefects,however,concentrationofwhichareNvariablestobesolvedforSimultaneousDefectEquilibriaExample:IntrinsicMgOTherearefourdefectsofinterestRelevantdefect-formingreactionsare:Therespectiveequilibriumconstant:Oneadditionalequationisnecessarycalledelectron-neutralityconditionExample:IntrinsicMgOTherearBrouwerApproximationAssumingasingledefectofeachsignhasaconcentrationmuchhigherthanothersofthesamesign,thereisjustonepositivedefectandonenegativedefectForpureMgO,fourBrouwerapproximationsarepossibleOnlyoneisimportantin(3)and(4)Athightemperature,(3)isdominantAtthelowestrangeofoxygenpressure,(1)islikelyimportantAtthehighestrangeofoxygenpressure,(2)islikelyimportantBrouwerApproximationAssumingDrawingBrouwerDiagraminthecenterregiondefinedbyOverthisregionKi1/2liesbelowKs1/2Withsufficientreduction

ThewidthofeachBrouwerregimeistemperature-dependentDrawingBrouwerDiagramintheSimpleProceduresforConstructingaBrouwerDiagramDeterminetherelevantdefectspecies/crystalstructure,soluteconcentration,andelectricalconductivityordiffusionratesWriteindependentdefectchemicalreactionsandtheirequilibriumconstantsGettheelectronneutralityapproximationwithonlyonenegativeandonepositivedefectUsetheBrouwerapproximationinthemass-actionrelationshiptosolveforPO2ObservewhichdefectconcentrationsareincreasingwithdecreasingorincreasingPO2SimpleProceduresforConstrucInteractionsBetweenPointDefectsandInterfacesgVxgVmFormationofanionandcationvacanciesatafreesurface.AdifferenceingVmandgVxcanleadtoaNonstoichiometriccation/anionratioatsurfaceandformationofexcesssurfacechargeInteractionsBetweenPointDefApplicationsofpointdefectschemistryinBaTiO3:

EffectsofoxygenpressureConductivityisntypeatlowpO2,ConductivityisptypeathighpO2nmContainingpredominantlyacceptorsasnaturalimpuritiesApplicationsofpointdefectsAssumption:1)theobservedconductivityisdeterminedbyeandhconc.;2)theeandhmobilitiesareindependentofpO2DifferentiateK(T)canbeestimatedfromtheminimaintheconductivityisothermsandaknowledgeofthemobilities.Assumption:1)theobservedcoAtlowoxygenpressurestheacceptor-compensatingoxygenvacancyconcentrationisregardedasinsignificantcomparedwiththatarisingthroughlossofoxygen:AtlowoxygenpressurestheacOxygenvacancyconcentrationnowdeterminedbytheacceptorimpurityconcentration[A]notPO2P-typecontributionOxygenvacancyconcentrationPO2>105PaPO2>105PaIntentionallyLa2O3donor-dopedBaTiO3IntentionallyLa2O3donor-dopeIntentionallyLa2O3donor-dopedBaTiO3AtlowestpO2values(AB)lossofoxygenfromthecrystal/withtheformationof

andelectronsIntentionallyLa2O3donor-dope《电子陶瓷》教学课件BandModelforBaTiO3BandModelforBaTiO3《电子陶瓷》教学课件《电子陶瓷》幻灯片本课件PPT仅供大家学习使用学习完请自行删除，谢谢！本课件PPT仅供大家学习使用学习完请自行删除，谢谢！《电子陶瓷》幻灯片本课件PPT仅供大家学习使用ElectronsandHoles

InanintrinsicS.Mlikesiliconattemperaturesaboveabsolutezero,therewillbesomeelectronswhichareexcitedacrossthebandgapintoC.VandwhichcanproducecurrentWhentheelectroninpuresiliconcrossesthegap,itleavesbehindanelectronvacancyor"hole"intheregularsiliconlatticeUndertheinfluenceofanexternalvoltage,boththeelectronandtheholecanmoveacrossthematerialInann-typesemiconductor,thedopantcontributesextraelectrons,dramaticallyincreasingtheconductivityInap-typesemiconductor,thedopantproducesextravacanciesorholes,whichlikewiseincreasetheconductivityElectronsandHolesInanintrP-andN-typeS.MP-andN-typeS.MBandsforDopedSemiconductorsTheapplicationofbandtheoryton-typeandp-typesemiconductorsshowsthatextralevelshavebeenaddedbytheimpurities.Inn-typematerialthereareelectronenergylevelsnearthetopofthebandgapsothattheycanbeeasilyexcitedintotheconductionband.Inp-typematerial,extraholesinthebandgapallowexcitationofvalencebandelectrons,leavingmobileholesinthevalenceband.BandsforDopedSemiconductorsP-njunctionTheopencirclesontheleftsideofthejunctionaboverepresent"holes"ordeficienciesofelectronsinthelatticewhichcanactlikepositivechargecarriers.Thesolidcirclesontherightofthejunctionrepresenttheavailableelectronsfromthen-typedopant.Nearthejunction,electronsdiffuseacrosstocombinewithholes,creatinga"depletionregion".TheenergylevelsketchaboverightisawaytovisualizetheequilibriumconditionoftheP-Njunction.Theupwarddirectioninthediagramrepresentsincreasingelectronenergy.P-njunctionTheopencirclesCompletep-njunctionAp-njunctioninthermalequilibriumwithzerobiasvoltageapplied.Electronsandholesconcentrationaredrawnrespectivelywithblueandredlines.Grayregionsarechargeneutral.Lightredzoneispositivelycharged.Lightbluezoneisnegativelycharged.Theelectricfieldisshownonthebottom,theelectrostaticforcebuildingbetweenelectronsandholesandthedirectioninwhichthediffusiontendstomoveelectronsandholes.Completep-njunctionAp-njunDepletionRegionWhenap-njunctionisformed,someofthefreeelectronsinthen-regiondiffuseacrossthejunctionandcombinewithholestoformnegativeions.Insodoingtheyleavebehindpositiveionsatthedonorimpuritysites.

Depletionregionisanon-conductinglayerDepletionRegionWhenap-njuMoreDetailInthep-typeregionthereareholesfromtheacceptorimpuritiesandinthen-typeregionthereareextraelectronsWhenap-njunctionisformed,someoftheelectronsfromthen-regionwhichhavereachedtheconductionbandarefreetodiffuseacrossthejunctionandcombinewithholesFillingaholemakesanegativeionandleavesbehindapositiveiononthen-side.Aspacechargebuildsup,creatingadepletionregionwhichinhibitsanyfurtherelectrontransferunlessitishelpedbyputtingaforwardbiasonthejunction.RecombinationMoreDetailInthep-typeregiCurrentinS.MBothelectronsandholescontributetocurrentflowinanintrinsicsemiconductorThecurrentwhichwillflowinanintrinsicS.Mconsistsofbothelectronandholecurrent.Thatis,theelectronswhichhavebeenfreedfromtheirlatticepositionsintotheconductionbandcanmovethroughthematerialInaddition,otherelectronscanhopbetweenlatticepositionstofillthevacanciesleftbythefreedelectrons.Thisadditionalmechanismiscalledholeconductionbecauseitisasiftheholesaremigratingacrossthematerialinthedirectionoppositetothefreeelectronmovement.CurrentinS.MBothelectronsaBiaseffectonelectronsinD.Z:Equilibriumofjunction

Coulombforcefromionspreventsfurthermigrationacrossthep-njunction.electronswhichhadmigratedacrossfromtheNtoPregioninformingofdepletionlayerhavenowreachedequilibrium.OtherelectronsfromtheNregioncannotmigratebecausetheyarerepelledbythenegativeionsinthePregionandattractedbythepositiveionsintheNregionBiaseffectonelectronsinD.BiaseffectonelectronsinD.Z:ReverseBias

ConnectingtheP-typeregiontothenegativeterminalofthebatteryandtheN-typeregiontothepositiveterminal,producesthereverse-biaseffectAnappliedvoltagewiththeindicatedpolarityfurtherimpedestheflowofelectronsacrossthejunction.Forconductioninthedevice,electronsfromtheNregionmustmovetothejunctionandcombinewithholesinthePregion.Areversevoltagedrivestheelectronsawayfromthejunction,preventingconduction.

BiaseffectonelectronsinD.BiaseffectonelectronsinD.Z:ForwardBias

Forward-biasoccurswhentheP-typesemiconductormaterialisconnectedtothepositiveterminalofabatteryandtheN-typeS.Mmaterialisconnectedtothenegativeterminal,asshownbelowAnappliedvoltageintheforwarddirectionasindicatedassistselectronsinovercomingthecoulombbarrierofthespacechargeindepletionregion.Electronswillflowwithverysmallresistanceintheforwarddirection.Or,youcansaythedepletionregionbecomesnarrowenoughBiaseffectonelectronsinD.Bandstructureofp-njunctionBandstructureofp-njunctionI–VCharacteristicsApnjunctionisanon-lineardevice,a“valve〞withan“easy〞anda“difficult〞currentdirectionIthasanonvoltageandabreakdownvoltageIVpnVIBreakdownprocessesarenon-destructiveandarereversibleI–VCharacteristicsApnjuncIntroductionpnandnpdiodecurrent-voltagecharacteristicsVIVIpnVIVInpThesecurrentsdonotobeytheOhm’slawIntroductionpnandnpdiodecuSchottkybarrierstoconductionsSchottkybarrierstoconductioSchottkyBarrierVariousSchottkybarrierdiodes:Smallsignalrfdevices(left),mediumandhighpowerSchottkyrectifyingdiodes(middleandright)ASchottkydiodeisaspecialtypeofdiodewithaverylowforward-voltagedropSchottkyBarrierVariousSchottSchottkyDiodeASchottkydiodeconsistofametallayeronasemiconductorsubstrateAccordingtothesimpleSchottkytheory,thebarrierheightFBthatexistsatthemetal/semiconductorinterfaceisgivenbyTheelectronsmustflowoverthebarrierwhenthedeviceisbiased-knownasthermionicemissionFBineVfBinV;FB=-qfBFBorfB?!what’sgoingonhere?ECEVV=0fBVbiVSchottkyDiodeASchottkydiodeSchottlyDiodesEnergyband

diagramofthemetalandthesemiconductorbefore(a)andafter(b)contactismade

SchottlyDiodesEnergybanddiaSchottlyDiodesSchottlyDiodesSchottkyDiodeThecurrent-voltagebehaviorofaSchottkydiodeisgivenbyVonVBDIV(A:area;A*:RichardsonConstant)ECEVV=0fBVbiVIncreasingfBSchottkyDiodeThecurrent-voltSchottkyDiodeThecurrent-voltagebehaviorofaSchottkydiodeissimilartothatofapnjunctionECEVV=0fBVbiECEVV<0BarrierisfBVbi+VECEVV>0BarrierisVbi-VElectronflowSchottkyDiodeThecurrent-voltMetal-n-S.MContactTheenergyfmrequiredtoremoveanelectronwiththeFermienergytoapointoutsidethemetalwithzero.Whenelectronsarethermallyexcitedoutofasemiconductor,theeffectiveworkfunctionfsofthesemiconductoristheenergydifferencebetweentheFermienergyandthevacuumlevel.Metal-n-S.MContactTheenergyOhmicContactTheaimofanohmiccontactprovidethecurrentthatthedevicerequiresthevoltagedropacrossthecontactshouldbelessthanthevoltagedropacrossthedeviceTherearetwoimpedimentsforcurrentflow:thebarrierheightandthebarrierwidthItisalmostimpossibletochangethebarrierheight,butwecanchangethebarrierwidthWbyincreasingthedopingdensityND

ECEFEVWThermionicemission(overthebarrier)SchottkyDiodeECEFEVWFieldemission(tunneling)(throughthebarrier)OhmicContactOhmicContactTheaimofanohmOhmicContactI-VchangessubstantiallyasthebarrierwidthchangesASchottkydiodeturnsintoanohmiccontactIVOhmicContactNDincreasesSchottkyDiodeOhmicContactI-VchangessubstOhmicContactCompletebanddiagramofapnjunctionIhavenevereverseenanenergybanddiagramlikethisbefore!p+pnn+OhmicTunnelContactOhmicTunnelContactTunnelingTunnelingAnimportantpropertyofEfisthat,forasysteminthermalequilibrium,itisconstantthroughoutthesystem.OhmicContactCompletebanddiaApplicationsMetal-semiconductordevicesfindapplicationsas:NonlinearSchottkydiodesRectifiers(canvarytheonvoltage)Highfrequencydetectors(majoritycarrierdevices)Gatesofcertainfield-effecttransistors(metal-semiconductorFETs)OhmiccontactsOhmiccontactsApplicationsMetal-semiconductoSummaryForward-biasandreverse-biaspropertiesofthep-njunctionimplythatitcanbeusedasadiode.Ap-njunctiondiodeallowselectricchargestoflowinonedirection,butnotintheoppositedirection;negativecharges(electrons)caneasilyflowthroughthejunctionfromntopbutnotfromptonandthereverseistrueforholesWhenthep-njunctionisforward-biased,electricchargeflowsfreelyduetoreducedresistanceofthep-njunctionWhenthep-njunctionisreverse-biased,however,thejunctionbarrier(andthereforeresistance)becomesgreaterandchargeflowisminimal....SummarySemiconductivityinOxidesModelsforoxidessystemaremuchmorecomplexthanforsiliconbecauseofPurityLimitationinOxidesSemiconductivityinOxidesModeElectronic/IonicCompensationofSolidsInacovalentS.M,theeffectivenessofdonorsandacceptorsissolelydeterminedbytheirionizationenergiesInoxideS.M,theydependsontheextentofoxidationandreductionAnaliovalentsoluteinanioniccompoundcanbecharge-compensatedbyionicdefectsorbyelectrons/holes,ormixedcompensationLargevariationsinelectricalconductivitycanresultwithchangesinPO2andTataconstantdopinglevel,duetochangesinthecompensationmechanismNote:Thetermionizationenergyismostcommonlyusedtorefertotheenergyrequiredtoremove(toinfinity)theoutermostelectronintheatomormoleculewhenthegasatomormoleculeisisolatedinfreespaceandisinitsgroundelectronicstateElectronic/IonicCompensationExample:IncorporationofNb2O5intoTiO2IoniccompensationElectronicCompensationOxidation/reductionequilibriumAtlowerNbconcentrations/higherT./lowerO2pressure,whichisdominant?AthigherNbconcentrations/lowerT./higherO2pressure,whichisdominant?Example:IncorporationofNb2OSimultaneousDefectEquilibria:BrouwerDiagramDefectformationreactionsofinterestwillgenerallyincludethosePredominantintrinsicionicdefects(SchottkyorFrenkel)IntrinsicelectronicdefectsOxidationandreductionIncorporationofanysignificantsolutesorimpuritiesThesereactionswillinvolveatotalofNdefects,however,concentrationofwhichareNvariablestobesolvedforSimultaneousDefectEquilibriaExample:IntrinsicMgOTherearefourdefectsofinteres