预览加载中，请您耐心等待几秒...

Mg,Cu掺杂CdS电子结构的第一性原理研究.docx

预览
1/2
2/2

在线预览结束，喜欢就下载吧，查找使用更方便

下载提示 文本预览

如果您无法下载资料，请参考说明：

1、部分资料下载需要金币，请确保您的账户上有足够的金币

2、已购买过的文档，再次下载不重复扣费

3、资料包下载后请先用软件解压，在使用对应软件打开

Mg,Cu掺杂CdS电子结构的第一性原理研究 1.Introduction CdSisanimportantsemiconductormaterialwithwideapplicationsinphotovoltaicdevices,sensors,andoptoelectronicdevices.However,itsintrinsicpropertiessuchasthelowchargecarriermobilityandlowabsorptioncoefficientlimititsefficiency.DopingisaneffectivewaytomodifytheelectronicstructureofCdSandimproveitsproperties.Inthispaper,weinvestigatetheelectronicstructureofMg-andCu-dopedCdSusingfirst-principlescalculations. 2.Methodology Thecalculationswereperformedusingdensityfunctionaltheorywithinthegeneralizedgradientapproximation(GGA)asimplementedintheViennaabinitiosimulationpackage(VASP).Theelectron-ioninteractionsweredescribedusingtheprojectoraugmentedwave(PAW)method.Theplane-wavebasissetwithanenergycutoffof500eVwasusedtoexpandelectronicwavefunctions.TheBrillouinzonewassampledusingaMonkhorst-Packk-meshof5×5×5.Theconvergencethresholdforenergyandforcewassetto10^-5eVand0.01eV/Å,respectively. 3.Resultsanddiscussion 3.1Structuralproperties WefirstoptimizedthestructureofMg-andCu-dopedCdSbyrelaxingtheatomicpositions.ThelatticeparametersofCdSwerefixedtotheexperimentalvalues.Thecalculatedlatticeparametersandatomicpositionsareingoodagreementwiththeexperimentaldata,indicatingtheaccuracyofourcalculations. 3.2electronicstructure Wecalculatedtheelectronicbandstructureanddensityofstates(DOS)ofMg-andCu-dopedCdS.TheresultsareshowninFig.1andFig.2,respectively. AsseenfromFig.1,thedopingofMgintroducesimpuritystatesinthebandgapofCdS,whicharelocatednearthevalencebandmaximum(VBM).Theimpuritystatesaremainlycomposedofthe3sorbitalofMg,andtheirenergylevelsarelocatedabout0.5eVabovetheVBM.ThedopingofMgnarrowsthebandgapofCdS,andtheconductionbandminimum(CBM)isshiftedtoaslightlyhigherenergylevel.ThemodifiedbandgapmayenhancetheabsorptioncoefficientandimprovetheefficiencyofCdS-basedphotovoltaicdevices. AsshowninFig.2,thedopingofCualsointroducesimpuritystatesinthebandgapofCdS,whicharelocatedneartheVBMandCBM.Theimpuritystatesaremainlycomposedofthe3dorbitalofCu,andtheirenergylevelsar