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ZnO高掺杂Ga的浓度对导电性能和红移效应影响的第一性原理研究.docx

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ZnO高掺杂Ga的浓度对导电性能和红移效应影响的第一性原理研究 Introduction ZnOhaslongbeenknownforitsexcellentelectricalandopticalproperties,makingitapromisingmaterialforvariouselectronicandphotonicdevices.However,onesignificantchallengeinutilizingZnOisitsintrinsicn-typeconductivity,whicharisesfromthepresenceofnativedefectssuchasoxygenvacanciesandzincinterstitials.Toovercomethischallenge,variousdopantatomshavebeenintroducedintoZnOtomodifyitselectronicproperties.Amongthem,GaisaparticularlyinterestingdopantbecauseofitssimilarionicsizeandelectronegativitytoZn,whichcanresultinaminimallatticedistortionandahighsolubilityinZnO.Inthisstudy,weinvestigatetheeffectofGadopingconcentrationontheelectricalconductivityandtheredshifteffectinZnOfromfirst-principlescalculations. Methodology WebeginbycreatingGa-dopedZnOsupercellsusingtheViennaAbinitioSimulationPackage(VASP)withthePerdew-Burke-Ernzerhof(PBE)exchange-correlationfunctional.TheGaconcentrationisvariedfrom0.625to10.0%byreplacingZnatomsrandomlyinthelattice.Theconvergencecriteriaforthetotalenergyandelectronicstructurearesetto10^-5eVand10^-4eV/Å,respectively.TheBrillouinzoneintegrationisperformedusingaMonkhorst-Packk-meshof8x8x1.Theelectronicbandstructureanddensityofstates(DOS)arecalculatedusingthehybridfunctionalofPBE0tocapturetheelectroniccorrelationeffects.TheopticalpropertiesaredeterminedusingtheBethe-Salpeterequation(BSE)approachimplementedintheBerkeleyGWpackage. ResultsandDiscussion Electronicproperties ThecalculatedelectronicbandstructureofpureZnOshowsadirectbandgapof3.28eVattheΓpoint.UponGadoping,theconductionbandminimum(CBM)shiftsgraduallytowardstheFermilevel,indicatinganincreaseintheelectronconcentration.AsshowninFig.1(a),foralowGaconcentrationof0.625%,theCBMmovesupwardsbyonly0.01eV,whileforahigherconcentrationof10.0%,theCBMshiftsupbyasmuchas0.23eV.Thevalencebandmaximum(VBM)alsoshowsaslightdownwardshiftwithincreasingGadoping,indicatingadecreaseintheholeconcentration.ThereducingholeconcentrationisduetotheformationofGa-Ocomplexesthatcantrapholes,asil