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ID:38963744
大小:531.50 KB
页数:11页
时间:2019-06-22
《Optical properties of CdTe below and above the band edge》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、OpticalpropertiesofCdTebelowandabovethebandgapP.HorodyskýandP.HlídekInstituteofPhysics,CharlesUniversity,PragueDirectmeasurementofinterbandabsorptiononverythinsamplesContentPreparationofthinsamplesAbsorptioncoefficientclosetotheenergybandgapQualityofultra-thinsamplesTemperaturede
2、pendenceoffreeexciton(FX)peakinabsorptionPreparationofthinsamplesStartingmaterial-highqualityCdTemonocrystalsMechanicalpolishingsamplesgluedonquartzorsaphiresubstrate(thickness1-5m)freestandingsamples(thickness10-20m)Chemicaletching(bybrom-methanol),removalofseveralmgluedsampl
3、es(onlyoneside)freestandingsamples(bothsides)Minimalthicknessgluedsamples0.8mfreestandingsamples4.8m(3x3mm2)CdTeSubstrateMicronthicksamplegluedonsubstrateAbsorptionspectraofthinandthicksamplesroomtemperatureAbsorptiontailonboth-sideetchedsampleismuchweakerEnergybandgapofCdTeat
4、RTis1.50-1.51eVAbsorptionedgeon‘thick’sampleisfarfromEgOccupationofedgestatesduringphotoluminescenceexcitationroomtemperatureRTPhotoluminescencearisesfrombothlocalisedandfreestatesbellowandaboveEgPhotoluminescencefromthinfree-standingsamplelowtemperaturePhotoluminescencefrom3m
5、belowthelong-timepolishedsurfaceehibitsonlyslightlymorebroadenedboundexcitonlinescomparedtostandardhigh-qualityPLspectrumAbsorptionofthinfree-standingsamplelowtemperatureModelforfittingthetransmittancespectrummodulatedbyinterferencebellowEg:lossesbyreflectanceR(E)+absorption(two
6、exponentialfunctionsforabsorptiontail)refractiveindexn(E)takenfromHlídeketal.,RefractiveindexofCdTe:Spectralandtemperaturedependence,J.Appl.Phys.90(4),2001AbsorptionandPhotoluminescencefromultra-thinsamplelowtemperatureMoredetails:Grilletal.,Defect-inducedopticaltransitionsinCdT
7、eandCd0.96Zn0.04Te,Semi.Sci.Tech.17,2002MoredetailsonFX+LOabsorption:Dillingeretal.,Phonon-AssistedExcitonTransitionsinAIIBVIsemiconductors,Phys.Stat.Sol.29,1968AbsorptionandPhotoluminescencefromultra-thinsamplelowtemperatureFXlinewidthoffree-standingsampleis3-4timesnarroverAbov
8、eEgabsorptiononafree-standingsamplenotac
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