近化学计量比钽酸锂晶体的拉曼光谱研究

346Vol.34No.6200512JOURNALOFSYNTHETICCRYSTALSDecember,20051,2,2,3,2,2,2,2,2,33,3,3,2,2,3,2,3(1.,300384;2.,300457;3.,300457):,,,,,,,278cm-1750cm-1,:;;;:O734:A:10002985X(2005)0621024206StudyonRamanSpectrumofNear2stoichiometryLithiumTantalateSHILi2hong1,2,KONGYong2fa2,3,YANWen2bo2,LIUHong2de2,LIXiao2chun2,XIEXiang2,XUJing2jun2,3,SUNJun3,CHENShao2lin3,ZHANGLing3,SUNLei2,ZHAODi2,ZHANGWan2lin3,ZHANGGuang2yin2,3(1.TianjinInstituteofUrbanConstruction,Tianjin300384,China;2.KeyLaboratoryofAdvancedTechniqueandFabricationforWeak2lightNonlinearPhotonicsMaterials,MinistryofEducation,NankaiUniversity,Tianjin300457,China;3.TianjinKeyLaboratoryofPhotonicsMaterialsandTechnologyforInformationScience,Tianjin300457,China)(Received10March2005,accepted18April2005)Abstract:TheRamanscatteringspectraoflithiumtantalatecrystalswithdifferentcompositionswereinvestigated.ThecomparisonoftheRamandataobtainedforthecongruentandthenear2stoichiometriccrystalsrevealssomedifferencesintheshapeandthenumberofRamanpeaks,whichleadtoanewassignmentofthelong2wavelengthopticalphonons.AndquantitativerelationshipsbetweenthelinewidthofRamanpeaks(142cm-1forE2phononand861cm-1forA12phonon)andthecrystalcompositionwerefirstlypresented.TwolocalRamanlines,278cm-1and750cm-1,werefoundforthecongruentcrystalsandattributedtotheintrinsicdefects,Livacancyandanti2siteTaion,respectively.Keywords:near2stoichiometry;lithiumtantalatecrystal;Ramanspectrum;defects1(LiTaO3,LT),[1,2][326],:20005203210;:2005204218:(No.60108001):(19792),,,E2mail:[e-mail]©1994-2006ChinaAcademicJournalElectronicPublishingHouse.Allrightsreserved.(CLT),,(SLT),Li,,,SLT[7,8]Li[9],LiTaO3,LiTaO3,LiTaO3,,2LiTaO3,1.2mmLiTaO3,(VTE)[10],:Li2CO3Ta2O5,10002h,,,VTELiLiTaO3Pt(),,Pt1200140h,LiLiLiTaO3,[11],48.7449.8mol%RenishawRamanscope2000,632.8nm,30mW,SPEX2140333.1,49.8mol%SLTCLT,Y(ZX)YE(TO),E(LO)A1(TO)Y(XX)Y12SLTCLT,SLTCLT,LiTaO31CLTSLTY(ZX)Y2CLTSLTE(LO)+A1(TO)Fig.1TheRamanspectraintheY(ZX)YconfigurationforCLTandSLT(thearrowspointthefrequencywherenewFig.2TheRamanspectraofE(LO)+A1(TO)peaksclearlyappearforSLTsampleandthepeakmodesforbothSLTandCLTsamplesintherelatedtoLivacancy(V-Li)forCLTsample)backwardscatteringconfigurations52016:©1994-2006ChinaAcademicJournalElectronicPublishingHouse.Allrightsreserved.(ZX)YY(XX)Y91319E(TO)SLT,,190cm-1,CLT208cm-1(SLN)150200cm-1E(TO)[12],190cm-1LiTaO3E(TO)3SLTE(TO)E(TO+LO)Fig.3TheRamanspectraofE(TO)andE(TO+LO)modesforbothSLTsampleintherightanglegeometryconfigurations(thearrowspointthepeaksclearlyappeared)tobeassignedtoE(LO)modesforSLTsample)2,1311A1(TO),11A1(TO)4,7E(LO)E(LO),LiTaO3X(ZX)Y,E(TO)E(LO)E(TO)X(ZY)Z3SLTE(TO)+E(LO)E(TO),190,280,343865cm-14E(LO)343865cm-1E(LO),7,E(LO)9,LiTaO3E(TO)E(LO)181LiTaO3,SLN3.2,Li,(LiNbO3,LN)[9],LiTaO3LiNbO3,E(TO)153cm-1A1(LO)876cm-1,LiTaO3,E(TO)142cm-1A1(LO)861cm-11Table1RamanpeakcharacteristicsforLiTaO3accordingtomanyresearchersRef.3Ref.4Ref.5Ref.6ThisworkSLN(Ref.12)E(TO)E(LO)E(TO)E(LO)E(TO)E(LO)E(TO)E(LO)E(TO)E(LO)E(TO)E(LO)74806970140163141200142142142142142142152.8186.5142190142194190190177.3194.9206248206206207278208280238.3240.4251278249275252280251314264.2299.0316318316345315315314314314343321.9345.0315380314344345379355378383452382459382463382445378380369.5424.2462474462470463463463463462462432.4456.0596648591659592866592865591661580.0625662870660866661865609.8878620134©1994-2006ChinaAcademicJournalElectronicPublishingHouse.Allrightsreserved.(YY)ZFig.4TheRamanspectraintheZ(YY)ZconfigurationforCLTandSLT(thearrowspointthefrequencywherenewpeaksclearlyappearforSLTsampleandthepeakrelatedtoTaanti2sitedefects(Ta4+Li)forCLTsample)LiTaO3142cm-1861cm-15,142cm-1Y(ZX)Y(1),861cm-1Z(YY)Z(4)Li6,,:CLi=51.45-0.2945(1)142cm-1CLi=52.42-0.1380(2)861cm-1,CLimol%,cm-16Fig.6LinewidthasthefunctionofthecrystalcompositionfortheRamanpeak:(a)at142cm-1and(b)at861cm-1inLiTaO3.Thedotsandlinesdonatetheexperimentalvaluesandfittingresults,respectively,,,0.05mol%[9,11],,,5LiTaO3Fig.5DependenceofRamanlinesinLiTaO3onthecrystalcomposition:(a)for142cm-1peakand(b)for861cm-1peak72016:©1994-2006ChinaAcademicJournalElectronicPublishingHouse.Allrightsreserved.(TO)278cm-1,SLT4750cm-17,7(a)278cm-1,7(b)750cm-1Li/Ta,,,CLT,Li(V-Li)Ta(Ta4+Li)7278cm-1(a)750cm-1(b)Fig.7Thecompositiondependenceof278cm-1peak(a)and750cm-1peak(b)[13]LiNbO3738cm-1Li,(Nb4+Li),A1(LO)750cm-1738cm-1,LiTaO3LiNbO3,750cm-1LiNbO3738cm-1(Nb4+Li)A1(LO)278cm-1,750cm-1LiTaO3VLiTa4+Li,Repelin[14]270400cm-1Li,VLiLi,270400cm-1,278cm-17278750cm-1,,,Stotal,(278cm-1260290cm-1,750cm-1730770cm-1),SS:Snormal=SStotalSnormal:CV-Li=F1S278normalCTa4+Li=F2S750normal,CV-LiLi(V-Li),278cm-1CTa4+Li,Ta(Ta4+Li),750cm-18Li(V-Li)Ta(Ta4+Li),:CV-Li=30.67S278normalCTa4+Li=182.01S750normal820134©1994-2006ChinaAcademicJournalElectronicPublishingHouse.Allrightsreserved.(a)the278cm-1peakand(b)thepeakdependenceoftheintrinsicdefectscontentThedotsandlinesdonatethecalculatedvaluesfromexperimentandfittingresu