简介:Theoperationprincipleofanarrayedwaveguidegrating(AWG)multiplexerisintroducedandthe4×4AWGwithfollowingdesignparametersisdiscussedindetail,suchasthechoiceofwavelength,theneighboringarrayedwaveguidedistanceΔL,thechannelfrequencyintervalΔf,andthefreespectralrange.Thestructureof4×4AWGisdesignedandtheresultofstimulatedtestisalsogiven.Analysisshowsthatthe4×4AWGischaracterizedbyawidedynamicrange,lowcrosstalk,betterspectrumproperties,andacompactstructure.
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.
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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.