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:美国半导体工业协会(SemiconductorIndustryAssociation,SIA)统计的数字显示,2009年7月全球半导体销售额为181亿5000万美元(3个月的移动平均值,以下相同),比上月增长5.3%。销售额已连续5个月比上月增加。今年7月份的销售额比上年同月减少了18.2%。虽然跌幅依然较大,但这是自2008年11月比上年同月减少9.7%以来跌幅首次低于20%。虽然增长速度缓慢,但半导体市场正在稳步恢复。全球半导体销售额恢复至180亿美元连续5个月超过上月业绩@章从福
简介:Organicmultiplequantumwells(OMQWs)consistingofalternatinglayersoforganicmaterialshavebeenfabricatedfromtris(8-hdroxyquinoline)aluminum(Alq)and2-(4-biphenylyl)-5-(4-tertbutylphenyl)-1,3,3-oxadiazole(PBD)byamultisource-typehigh-vacuumorganicmoleculardeposition.Fromthesmall-angleX-raydiffractionpatternsofAlq/PBDOMQWs,aperiodicallylayeredstructureisconfirmedthroughtheentirestack.TheAlqlayerthicknessintheOMQWswasvariedfrom1nmto4nm.Fromtheopticalaborption,photoluminescenceandelectroluminescencemeasurements,itisfoundthattheexcitonenergyshiftstohigherenergywithdecreasingAlqlayerthickness,ThechangesoftheexcitonenergycouldbeinterpretedastheconfinementeffectsofexcitonintheAlqthinlayers.Narrowingoftheemissionspectrumhasalsobeenobservedfortheelectroluminescentdevices(ELDs)withtheOMQWsstructureatroomtemperature.