简介:Inthisstudy,weevaluatethevaluesoflatticethermalconductivityκLoftypeIIGeclathrate(Ge34)anddiamondphaseGecrystal(d-Ge)withtheequilibriummoleculardynamics(EMD)methodandtheSlack'sequation.ThekeyparametersoftheSlack'sequationarederivedfromthethermodynamicpropertiesobtainedfromthelatticedynamics(LD)calculations.TheempiricalTersoff'spotentialisusedinbothEMDandLDsimulations.Thethermalconductivitiesofd-Gecalculatedbybothmethodsareinaccordancewiththeexperimentalvalues.ThepredictionsoftheSlack'sequationareconsistentwiththeEMDresultsabove250KforbothGe34andd-Ge.Inatemperaturerangeof200-1000K,theκLvalueofd-GeisaboutseveraltimeslargerthanthatofGe34.
简介:TheultrafastdynamicprocessinsemiconductorGeirradiatedbythefemtosecondlaserpulsesisnumericallysimulatedonthebasisofvanDrielsystem.Itisfoundthatwiththeincreaseofdepth,thecarrierdensityandlatticetemperaturedecrease,whilethecarriertemperaturefirstincreasesandthendrops.ThelaserfluencehasagreatinfluenceontheultrafastdynamicalprocessinGe.Asthelaserfluenceremainsaconstantvalue,thoughtheoverallevolutionofthecarrierdensityandlatticetemperatureisalmostindependentofpulsedurationandlaserintensity,increasingthelaserintensitywillbemoreeffectivethanincreasingthepulsedurationinthegenerationofcarriers.IrradiatingtheGesamplebythefemtoseconddoublepulses,theultrafastdynamicalprocessofsemiconductorcanbeaffectedbythetemporalintervalbetweenthedoublepulses.
简介:GrazingincidentX-raydiffractionatdifferentgrazinganglesforself-organizedGedotsgrownonSi(001)arecarriedoutandlatticeconstantexpansionsof1.2?paralleltothesurfaceascomparedwiththeSilatticearefoundwithintheGedots.A3.1?latticeexpansionoftheGedotsalongthegrowthdirectionisalsofundbyordinaryX-ray(004)diffraction.AccordingtothePoissonequationandtheVegardlaw,ourresultsinferthattheGedotshouldbeapartiallystrainrelaxedSiGealloywithGecontentofabuot55?2001ElsevierScienceB.V.Allrightsreserved.
简介:ZnOfilmscontainingErandGenanocrystals(nc-Ge)weresynthesizedandtheirphotoluminescence(PL)propertieswerestudied.Visibleandnear-infraredPLintensitiesarefoundtobegreatlyincreasedinnc-Ge-containingfilm.Er-related1.54μmemissionhasbeeninvestigatedunderseveralexcitationconditionsupondifferentkindsofGe,ErcodopedZnOthinfilms.1.54μmPLenhancementaccompaniedbytheappearanceofnc-Geimpliesasignificantcorrelationbetweennc-GeandPLemissionofEr3+.Theincreasedintensityof1.54μminGe:Er:ZnOfilmisconsideredtocomefromthejointeffectofthelocalpotentialdistortionaroundEr3+andthepossibleenergytransferfromnc-GetoEr3+.
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简介:Inthispaper,high-speedsurface-illuminatedGe-on-Sipinphotodiodeswithimprovedeffidencyaredemon-strated.Withphoton-trappingmicroholefeatures,theexternalquantumefficiency(EQE)oftheGe-on-Sipindiodeis〉80%at1300nmand73%at1550nmwithanintrinsicGelayerofonly2μmthickness,showingmuchimprovementcomparedtoonewithoutmicroholes.MorethanthreefoldEQEimprovementisalsoob-servedatlongerwavelengthsbeyond1550nm.Theseresultsmakethemicrohole-enabledGe-on-SiphotodiodespromisingtocoverboththeexistingCandLbands,aswellasanewdatatransmissionwindow(1620-1700nm),whichcanbeusedtoenhancethecapacityofconventionalstandardsingle-modefibercables.Thesephotodiodeshavepotentialformanyapplications,suchasinter-/intra-datacenters,passiveopticalnetworks,metroandlong-hauldensewavelengthdivisionmultiplexingsystems,eye-safelidarsystems,andquantumcommunications.TheCMOSandBiCMOSmonolithicintegrationcompatibilityofthisworkisalsoattractiveforGeCMOS,near-infraredsensing,andcommunicationintegration.
简介:WehavesynthesizedandinvestigatedphysicalpropertiesoftwonewquaternarycompoundsGd2CoAl4T2(T=Si,Ge)singlecrystals,whichareisostructuraltoTb2NiAl4Ge2andEr2CoAl4Ge2.Themostimportantstructuralfeatureofthesematerialsistheanti-CaF2-typeCoAl4T2slabs.Thesematerialsshowmetallicbehaviorbelow300Kandthereisalong-rangeantiferromagnetic(AFM)transitionappearingat20and27KforGdCoAl4Ge2andGd2CoAl4Si2,respectively.ResistivityandheatcapacitymeasurementsalsoconfirmthesebulkAFMtransitions.Furtheranalysisindicatesthatthislong-rangeantiferromagnetismshouldresultfromthemagneticinteractionbetweenlocalmomentsofGd^3+ions.
简介:做Si的Ge(2)sb(2)Te(5)电影被dc劈啪作响magnetronco与Ge2Sb2Te5和Si目标准备了。在在两结晶化温度和阶段转变温度fromface-centred-cubic(fcc)的增加的Te(5)电影结果分阶段执行到的Ge(2)sb(2)的Si的增加六角形(十六进制)阶段。Ge2Sb2Te5电影的抵抗力显示出重要增加,Si做。当在这部电影做Si的11.8at.%时,在退火的460度C以后的抵抗力与undopedGe2Sb2Te5电影相比从64~99终止从1~11m终止(.)厘米和动态抵抗增加增加。这对写阶段变化随机存取记忆的当前的减小很有用。
简介:用费波那契数列(FibonacciSequence)计算规则联接的电阻、电容网络的等效值,方法特别且较常规的电阻(电容)串并联解法方便、快捷。
简介:在相同的反应体系中当ph值从约9.5调变至11时分别合成出双中孔SiO2和六方中孔SiO2材料,并用XRD、N2吸附、TEM、TG/DTA和FTIR等测试手段对合成产物进行了表征。实验结果表明,双中孔SiO和六方中孔SiO2是合成中必然出现的两种不同的中孔物相。与六方中孔SiO2相比,双中孔SiO2也具有典型中孔材料的特征XRD谱图,虽然仅呈现一个易让人产生不完全晶化误解的相对较宽的单XRD衍射峰(d=5.2nm),但它却给出一种独特的N2吸附等温线和窄的双峰中孔孔径分布曲线。由于孔壁的无定形及表面活性剂分子与SiO2骨架间相似的相互作用,两类材料给出类似的FTIR谱图和TG/DTA曲线。然而,在双中孔SiO2的FTIR谱图中960cm处峰强度的微小变化可能意味着在锻烧脱除模板剂后双中孔SiO2较六方中孔SiO2具有更高的骨架聚合度。更多还原