简介：Geepilayersofdifferentthicknessesaregrownbymolecular-beamepitaxywithSbasasurfactantonSI(100)substrates,X-raydiffractionillustratesthattheseGethinfilmsarepartiallystrained.andthestrainsdecreasegraduallywithincreasingepilayerthickness,RamanspectrarevealadownwardshiftoftheGe-Gemodepeakastheepilayerthicknessincreases.Intheregionsofhighstrain,therelationshipbetweentheRamanshiftofthismodeandthestraininthepartiallyrelaxedsamplesisconsiderablydifferentfromthelinearrelationshipreportedbefore,whichismainlyattributedtothespatialconfinementeffectofphononsinananocrystal.

简介：

简介：利用同步辐射掠入射和常规X射线衍射，对Si(001）衬底上自组织生长Ge量子点组分和应变进行了研究。结果表明量子点为50％应变驰豫的GeSi合金量子点，其Ge组分为0．55。此外在掠入射X射线衍射Si(220）峰的高角旁观察到另外一个峰，对应于量子点周围衬底中由成岛引起的压应变。

简介：低温下用MBE方法生长了Ge／Si超晶格。X射线近边吸收限精细结构研究表明，Ge与Si再Ge／Si界面处存在化学混合。X射线反射及横向散射研究表明，Ge亚层上下表面的粗糙度呈反对称，下表面大的粗糙度来源于Ge向Si亚层中扩散形成SiGe混合组分结构：这种组分结构可以用一平均成份的SiGe合金层加以拟合，从而使得各亚层均有一个合理的粗糙度。旋转样品进行的X射线散射研究表明，这种SiGe的混合是各向同性的，这与透射电子显微镜的研究结构相一致。

简介：

简介：TheballmillingofFe-24MnandFe-24Mn-6Simixedpowdershasbeenperformedbythehighenergyballmillingtechnique.ByemployingX-raydiffractionandMoessbauermeasurements.Theccmpositionevolutionduringthemillingprocesshasbeeninvestigated.TheresultsindicatetheformationofparamagneticFe-MnorFe-Mn-Sialloyswithametastablefccphaseasfinalproducts.whichimplythattheFeandMnproceedaco-diffusionmeenanismthroughthesurfaceoffragmentedpowders.Thethermalstabilityandcompositionevolutionoftheas-milledalloyswerediscussedcomparingwiththebulkalloy,.

简介：

简介：Amorphoussilicon(a-Si),nanocrystallinesilicon(nc-Si)andhydrogenatednanocrys-tallinesilicon(nc-Si:H)filmswerefabricatedbyusingchemicalvapordeposition(CVD)system.Thea-Siandnc-Sithinfilmswereirradiatedwith94MeVXe-ionsatfluencesof1.0×1011ions/cm-2,1.0×1012ions/cm-2and1.0×1013ions/cm-2atroomtemperature(RT).Thenc-Si:Hfilmswereirradiatedwith9MeVXe-ionsat1.0×1012Xe/cm-2,1.0×1013Xe/cm-2and1.0×1014Xe/cm-2atRT.Forcomparison,mono-crystallinesilicon(c-Si)sampleswerealsoirradiatedatRTwith94MeVXe-ions.AllsampleswereanalyzedbyusinganUV/VIS/NIRspectrometerandanX-raypowderdiffractometer.Variationsoftheopticalband-gap(Eg)andgrainsize(D)versustheirradiationfluencewereinvestigatedsystematically.Theobtainedresultsshowedthattheopticalband-gapsandgrainsizeofthethinfilmschangeddramaticallywhereasnoobservablechangewasfoundinc-SisamplesafterXe-ionirradiation.Possiblemechanismunderlyingthemodificationofsiliconthinfilmswasbrieflydiscussed.

简介：TherearetwotpyesofphasetransformationsinFe-MnandFe-Mn-Sialloyswhenthetemperatureisdecreased,γ(fcc)→ε(hcp)martensitictransformation(MT)andparamagnetic-antiferromagnetictransition(AMT)ofγphase.Fromthethermodynamicpointofview,theformerusuallyappearsinaslightlyhighertemperaturerangethanthelatterbecauseifisgenerallyacceptedthatthemagnetictansitionhasasuppressingeffectonthethermallyinducedεmartensite(Satoetal.,1984.,BogachevandZvigintzeva,1976;Murakamietal.,1987:Yangetal.,1992)GartsteinandRobinkin(1979)eventhoughtthattheγ-εtransformationshouldbeterminatedbelowNeeltemperature(TN)duetothedecreaseoffreeenergyarisingfromtheAMTofγphase.However,someexperimentalresultshaeindicatedtheformationofεphasebelowT(LiandWayman,1994:Fujimori.1966).Inthepresentwert.thebehavorofγ-εtransformationbelowTNwasfurtherinvestigatedbyclectricalresistancemeasurements.

简介：MoleculardynamicssimulationsareperformedtoinvestigateCF3continuouslybom-bardingtheamorphoussiliconsurfacewithenergiesof10eV,50eV,100eVand150eVatnormalincidenceandroomtemperature.TheimprovedTersoff-Brennerpotentialswereused.Thesimu-lationresultsshowthatthesteady-stateetchingratesareabout0.019,0.085and0.1701for50eV,100eVand150eV,respectively.Withincreasingincidentenergy,atransitionfromC-richsurfacetoF-richsurfaceisobserved.IntheregionmodifiedbyCF3,SiFandCFspeciesaredominant.

简介：

简介：用X射线摇摆曲线和掠入射衍射、透射电镜、原子力显微镜等实验技术研究了MBE方法生长的Si缓冲层生长温度对SiGe／Si异质结结构的影响。结果表明，所研究的SiGe外延层晶格发生完全弛豫，但表面粗糙度和界面失配位错随Si缓冲层的生长温度而变化，最佳生长温度为450℃；缓冲层晶格应变是达到高质量SiGe外延层的主要原因。

简介：

简介：通过同步X光荧光（SXRF）成分分析，定性地研究了在0．5atm、0.6atm、0.7atmAs压下1150℃进行退火处理后衬底化学与比的变化。结果表明：控制As压可以改变化学配比，在足够As压下的高温退火将改善化学配比均匀性。

简介：GaInP/GaAs/Getriple-junctionsolarcellswereirradiatedwith50keVand100keVprotonsatfluencesof5×1010cm-2,1×1011cm-2,1×1012cm-2,and1×1013cm-2.Theirperformancedegradationisanalyzedusingcurrent-voltagecharacteristicsandspectralresponsemeasurements,andthenthechangesinIsc,Voc,Pmaxandthespectralresponseofthecellsareobservedasfunctionsofprotonirradiationfluenceandenergy.Theresultsshowthatthespectralresponseofthetopcelldegradesmoresignificantlythanthatofthemiddlecell,and100keVproton-induceddegradationratesofIsc,VocandPmaxarelargercomparedwith50keVprotonirradiation.

简介：

简介：

简介：TheNi-AlalloycontainingCr,FeadditiveswerepreparedasRaneyNiCatalystbyhighenergymilling.ThesizeandsurfacestateofNi-Alalloypowderwerestudiedbyparticlesizeanalyzerandsanningelectronmicroscopy.theStructurewasanalyzedbyXRDandMoessbauermethods.Theresultsshowedthatafterahigh-energymilling(HEM).theNi-Alalloytransformstoanano-scaleNiAlstructurewithrichAl.Byannealingthealloy,ametastableNi2Al3phasecanbeobtained.

简介：

简介：