Cu-Se復合物半導體薄膜的成分分析

Contents,CuInSe2,CuInSe,第-III-VI族元素化合物半導體，為直接帶隙半導體，禁帶寬度1.04eV。,CuInSe2薄膜太陽能電池結構,CuInSe2薄膜電池,Cu-Sebinarysystem,溶劑熱法光化學化學氣相沉積（CVD）電沉積,廣泛應用于無機半導體的沉積。薄膜生長：簡單、成本低、條件溫和、自身可控的生長率和薄膜成分。,Cu-Se合成方法,Inthisreport,wedescribeanewelectroanalyticalrouteusingcombinedEQCMandstrippingvoltammetryforthecompositionalanalysisofCu-Sethinfilmselectrodepositedatdifferentpotentials.,實驗部分,Forflow-EQCMexperiments,anEG&GPrincetonAppliedResearchModel273AsystemwasusedandfrequencychangesweredisplayedonaKippandZonenModelBD111singlepenchartrecorder.AGilsonMinipuls3peristalticpumpwasusedtodeliversolutiontotheflowEQCMsystemandaValcoModel6-wayslidervalveequippedwith0.15mmi.d.tubingwasemployedtoswitchandinjectsolutionsatanominalflowrateof0.28mL/min.Theflowrateandacellvolume(about0.5mL)wereenoughforthedepositionofthinfilmsconsideringtheconcentrationofCu2+andSe4+ions.,結果討論,Figure1.Linearsweepvoltammograms(solidline)andthecorrespondingEQCMfrequencychanges(dashedline)forthestrippingof(a)Sein0.1MNa2SO4solution.Scanrate:10mV/s.,(b)Cu2Sein0.1MNa2SO4solution.Scanrate:10mV/s.,TodifferentiatethepeakduetoSereductionfromthatarisingfromCu2Sereduction,Cu-Sefilmwaselectrodepositedat0.1Vusing0.1MH2SO4containing10mMSeO2and5mMCuSO4.AfterthefreeSewasremovedfromthefilmbyapplying0.7Vfor100sin0.1MNa2SO4blankelectrolyte.,ElectrodepositionofCu2Sewasconfirmedbythecathodicphotocurrentofthefilmuponlightillumination,whichisconsistentwithp-typesemiconductorbehavior.Inordertofurtherassignthepeakat0.98VinFigure1b,thenumberofelectrons(n)transferredduringthereductionwascalculatedfromtheslopeofcharge-frequencyplot:Q=(nFk/M)f(1)InEq.(1),Qischarge,FisFaradayconstant,kissensitivityfactor,Mismolarmassandfisfrequencychanges.Thenvalueobtainedfromtheslopewasfoundtobe1.9,whichclearlyshowsthatthepeakisduetoreductionofCu2Se:Cu2Se+2e=2Cu+Se2(2),(c)Cuin0.1MNa2SO4solution.Scanrate:10mV/s.,apre-electrodepositedCufilmwasanodicallystrippedin0.1MNa2SO4blankelectrolyte(Figure1(c).TheCufilmwaselectrodepositedat0.1Vfor60susing0.1MH2SO4containing5mMCuSO4.,Figure2.Linearsweepvoltammograms(solidline)andthecorrespondingEQCMfrequencychanges(dashedline)forthecathodicstrippingofCu-Sethinfilmsin0.1MNa2SO4solution.Thinfilmswereelectrodepositedat(a)0.1Vand(b)0.3Vfor4kHzusing0.1MH2SO4containing10mMSeO2and5mMCuSO4.Scanrate:10mV/s.,Now,thecompositionofelectrodepositedCu-Sethinfilms(freeCu,freeSeandCu2Se)wasdeterminedusingcombinedstrippingvoltammetryandflow-EQCM.,Figure3.EQCMfrequency(mass)changesduringtheelectrodepositionandstrippingsteps.ElectrolytesforelectrdepositionandstrippingweresameasinFigure2.,Figure4.CompositionalvariationofCu-SefilmselectrodepositedatdifferentpotentialsanddeterminedbytheproceduredescribedinFigure3.Theerrorbarsdenoteonestandarddeviation.,ThenthetotalCu(freeCu+CuinCu2Se)wasdeterminedviaanodicstrippingat+0.8VandfreeCucontentwascalculatedfromthedifferencebetweentotalCuandCuinCu2Se.,Figure5.(a)Linearsweepvoltammogramsand(b)thecorrespondingEQCMfrequencychangesforCu-Sefilmsin0.1MNa2SO4.Cu-Sefilmswereelectrodepositedat0.1Vfor16kHzusing0.1MH2SO4containing10mMSeO2and5mMCuSO4.Scanrate:10mV/s.,Duringthefirst1kHz(lessthan10nmthick),thefilmalmostconsistsoffreeSeandfreeCu.However,theamountofCu2Seincreasedasthefilmthicknessincreasesfrom1kHzto6kHzordepositiontimeincreasesasseeninFigure5.Thisbehaviorrevealsthatpost-chemicalreactionbetweentwoelementsresultsintheformationofCu2Sebinarycompound,Summary,Insummary,anovelmethodwhichisspeciesselectiveforthecompositionalanalysisofelectrodepositedCu-Sesemiconductorfilmswasdevelopedusingcombinedvoltammetryandflow-EQCM.TheamountsoffreeSeandSeinCu2Sewereobtainedfromthefrequencychangesatconstantpotentialsof0.8Vand1.3V,respectively.Potentialstepsto0.8Vand1.3VwereemployedtoreducefreeSetoSe2andCu2SetoCu+Se2,respectively.ResultanttotalCuwasanodicallystrippedat+0.8VandthefreeCucontentwascalculatedusi