K离子弱掺杂ZnO薄膜的光电性能研究.docx

K离子弱掺杂ZnO薄膜的光电性能研究
摘要：
本文研究了K离子对ZnO薄膜光电性能的影响。采用射频磁控溅射法制备了K离子弱掺杂的ZnO薄膜，并对其进行了结构、光学和电学性能的表征。结果表明，K离子掺杂可以显著改善ZnO薄膜的光电性能，包括提高光吸收能力、增加导电性、减小缺陷密度等。当K离子掺杂浓度为2%时，ZnO薄膜的最大吸收峰红移至395nm，电导率增加了10倍，缺陷密度则减小了50%。这些结果表明，K离子掺杂是一种有效的方法来改善ZnO薄膜的光电性能。
关键词：K离子掺杂；ZnO薄膜；光电性能；射频磁控溅射
Introduction:
Zincoxide(ZnO)isawide-bandgapsemiconductormaterialwithmanypromisingapplications,suchassolarcells,sensors,transparentelectrodesandoptoelectronicdevices.However,theperformanceofZnO-baseddevicesisoftenlimitedbytheintrinsicdefectsandpoorelectricalpropertiesofZnO,suchasthehighresistivityandlowcarrierconcentration.InordertoimprovetheoptoelectronicpropertiesofZnO,variousdopingmethodshavebeendeveloped,suchasdopingwithtransitionmetalelements,rareearthelements,andalkalimetalelements.Inthiswork,wefocusedontheeffectofpotassium(K)iondopingontheoptoelectronicpropertiesofZnO,asKisanabundantandlow-costelementthathasbeenreportedtoenhancetheelectricalconductivityandimprovethecrystalqualityofZnO.
Experimentalsection:
K-dopedZnOthinfilmswerepreparedbyradiofrequencymagnetronsputteringonglasssubstrates.ThedepositionwascarriedoutatroomtemperatureinanAratmospherewithaflowrateof25sccmandapressureof5mTorr.ThetargetwasaZnOceramicdiskwith2wt%K2CO3powderaddedasthedopantsource.Thepowerdensitywasfixedat1.2W/cm2,andthedepositiontimewassetto30min.TheKdopingconcentrationwascontrolledbyvaryingtheweightpercentageofK2CO3inthetarget.Theas-depositedfilmswereannealedat400°Cfor2hinairtoimprovethecrystallinityandremovetheresidualcarbon.
ThecrystalstructureofthesampleswascharacterizedbyX-raydiffraction(XRD)usingaRigakuD/MAX-2200diffractometerwithCuKαradiation.TheopticaltransmittanceandabsorbancespectraweremeasuredbyaUV-Vis-NIRspectrophotometer.TheelectricalpropertieswereinvestigatedbyHalleffectmeasurementsusingaLakeshore8400Hallsystem.
Resultsanddiscussion:
TheXRDpatternsoftheZnOfilmswithdifferentKdopingconcentrationsareshowninFigure1.Allthesamplesexhibitedahexagonalwurtzitestructurewith(002)preferredorientation,indicatingthefilmgrowthalong