简介:TheinvestigationonopticalpropertiesofSi1-xGex/Sistrainedlayerstructureshasbeencarriedoutactivelyinrecentyears.Thephotoluminescencehasbe-comeabriskersubjectinthestudiesofitsvariousopticalproperties.Aresearchdevelop-menttophotoluminescencepropertiesofsomenewSi1-xGex/Sistrainedlayerstruc-turesisintroduced.
简介:UsingdoublecrystalX-raysdiffraction(DCXRD)andatomicforcemicroscopy(AFM),theresultsofGexSi1-xgrownUHV/CVDfromSi2H6andSiH4areanalyzedandcompared.Adsorbatescanmigratetotheenergy-favoringpositionduetotheslowgrowthratefromSiH4.Inthiscase,aSibufferthatisolatestheeffectofsubstrateonepilayercouldnotbegrown,whichresultsinapitpenetratingintoepilayerandbuffer.TheFWHMis0.055°inDCXRDfromSiH4.Thepresenceofdiffractionfringesisanindicationofanexcellentcrystallinequality,TheroughnessofthesurfaceisimprovedifgrownbySi2H6:however,thecrystalqualityoftheGex2Si1-xmaterialbecameworsethanthatfromSiH4duetomuchlargergrowthratefromSi2H6.ThecontentofGeisobtainedfromDCXRD,whichindicatesthegrowthratefromSi2H6islargest,thenGeH4andthatfromSiH4isleast.
简介:Anultrahighvacuumchemicalvapordeposition(UHV/CVD)systemisintroduced.SiGealloysandSiGe/Simultiplequantumwells(MQWs)havebeengrownbycold-wallUHV/CVDusingdisilane(Si2H6)andgermane(GeH4)asthereactantgasesonSi(100)substrates.ThegrowthrateandGecontentsinSiGealloysarestudiedatdifferenttemperatureanddifferentgasflow.ThegrowthrateofSiGealloyisdecreasedwiththeincreaseofGeH4flowathightemperature.X-raydiffractionmeasurementshowsthatSiGe/SiMQWshavegoodcrystallinity,sharpinterfaceanduniformity.Nodislocationisfoundintheobservationoftransmissionelectronmicroscopy(TEM)ofSiGe/SiMQWs.TheaveragedeviationofthethicknessandthefractionofGeinsingleSiGealloysampleare3.31%and2.01%,respectively.
简介:Theresidualelectricallyactivedefectsin(4×1012cm-2(30KeV)+5×1012cm-2(130KeV))si-implantedLECundopedsi-GaAsactivatedbytwo-steprapidthermalannealing(RTA)LABELEDAS970℃(9S)+750℃(12S)havebeeninvestigatedwithdeepleveltransientspec-troscopy(DLTS).TwoelectrontrapsET1(Ec-0.53eV,σn=2.3×10-16cm2)andET2(Ec-0.81eV,σn=9.7×10(-13)cm2)aredetected.Furthermore,thenoticeablevariationsoftrap’scon-centrationandenergylevelintheforbiddengapwiththedepthprofileofdefectsinducedbyionim-plantationandRTAprocesshavealsobeenobserved.The[Asi·VAs·AsGa]and[VAs·Asi·VGa·AsGa]areproposedtobethepossibleatomicconfigurationsofET1andET2,respectivelytoexplaintheirRTAbehaviors.
简介:日前,国家广电总局正式颁布了中国移动多媒体广播,即“手机电视”的行业标准,向“手机电视时代”迈出了关键性的一步。国家广电总局确定的手机标准为有自主知识产权的STiMi标准,并将于今年11月1日起正式实施。STiMi标准的胜出,意味着韩国T—DMB、美国MediaFlo、日本ISDB—T和欧洲DVB-H四大国际标准,将退出国内手机电视市场的竞争。此前,国外标准的支持厂商已经开始在国内“试水”手机电视,如以NOKIA为首的欧洲DVB—H阵营,曾陆续在北京、福建搭建实验网络;而以高通公司为首的FLO论坛,也吸引了包括夏新在内的三家中国合作伙伴。
简介:PhotoconductivityCharacteristicsofPorousSi①CHAOZhanyun,WANGKaiyuan(DepartmentofElectronicEnginering,SoutheastUniversity,Nanji...
简介:AninitialstructuredesignofMMI1×8opticalpowersplittersisreported.ThewaveguidematerialisSi-basedSiO2Ge-dopedanddepositedbyPECVDmethod.Embeddedstripstructureisimpliedinthesectiondesign.ByusingBPM-CAD,afavorableresultisobtainedthatthisdevicehasasounduniformityandfairlylowloss.Meanwhile,simulationsofdesignswithcertainchangedparametersisalsoimplementedforabetterdesignconfiguration.
简介:Aconductionchannelmodelispropsedtoexplainthehighconductivitypropertyofnc-Si:H.Detailedenergybanddiagramisdevelopedbasedontheanalysisandcalculation,andtheconductivityofthenc-Si:Hwasthenanalysedonthebasisofenergybandtheory.Itisassumedthattheconductivityofthenc-Si:Hstemsfromtwoparts:theconductanceoftheinterface,wherethetransportmechanismisidentifiedasathermal-assistedtunnelingprocess,andtheconductancealongthechannelaroundthegrain,whichmainlydeterminedthehighconductivityofthenc-Si:H.Theconductivityofnc-Si:Hiscalculatedandcomparedwiththeexperimentdata.Thetheoryisinagreementwiththeexperiment.
简介:Theeffectofhydrogenpassivationonmulticrystallinesilicon(mc-Si)usedforsolarcellsisdescribed,andthemechanismofhydrogendiffusionandpassivationisalsoinvestigated.Then,thehydrogenpassivationprocessesappliedinindustriesandresearchlaboratoriesareintroduced.Finallytheexistingproblemsandtheprospectsofhydrogenpassivationarereviewed.