PROGRAM FOR中国科学院国际材料物理中心

PROGRAMPROGRAM FORFOR 中国科学院国际材料物理中心中国科学院国际材料物理中心 IMR Symposiumon Materials Sciences andEngineering Frontier andFuture of Advanced Functional MaterialsE mail zcfeng ee ntu tw Web eoe ntu tw ee ntu tw In the past20th century Si hasdominated thesemiconductor materialsmarket while GaAs InP oupiedthe mostof semiconductoroptoelectronics market Recently research onother semiconductormaterials foroptoelectronics andelectronics applicationshas attractedmuch attention including porousSi SiGe III Nitrides SiC isthe firstsemiconductormaterialto achievethe bluecolor light emitting diode LED and to use for the powerand microwaveelectronics in the20th century However the difficultyin epitaxyand growinglarge sizeSiC crystalhas limitedits development Advances inSiC epitaxyon Sisubstrate andbulk growthtechnology developedsince1980 shaverevitalized theinvestigation of SiC Commercial availabilityof larger than twoinch wafersin thepast decadehas putSiC technologya mercialreality This reportwill reviewthe mainadvances on SiC materials devices and applications inhistory andrecent years many ofwhich aredescribed intwo recentreview bookson SiCedited by the author The workfrom the speaker collaborator andother famouspanies institute and universities in recent twodecades willbe introduced The uniquematerial properties of SiCand betterunderstandings on the SiCmaterials physicswillbesummarized Although III N LEDsare currentlyattracting greaterattention SiC optoelectronicdevices stillhave theirattractive featuresand uniqueapplications for example avalanche photodetectors APDs The uniquematerial properties ofSiC should makeSiC APDsmuch moreattractive inparison toIII N counterparts Optically activatedpower devicesbased on SiCshouldalso outperformIII N devices Current SiCresearch focusis onhigh speedand highpower devices it is expected that the newbreakthrough in these fieldsmay einto beingsoon in the early21st century These wouldcause importantinfluences onpower stationand electriontrol systems automobiles aircrafts radars andmunication defense andanti terrorism After the development in thepasthalf centuryfor the1st generationSi based semiconductormaterials and industry and the2nd generationof GaAs InP based it isvery promisingfor SiC together withIII N andother widegapmaterials as the3rd generationmaterials forthe baseof newelectronic andoptoelectronic industry It ishopeful tosee furtherdevelopments tomeet thenew challengingandindustrydevelopment ofSiC era Two recentreview booksonSiCedited bythespeakerwillbeintroduced also Advanced scanningprobe techniquesapplied tonano structured materialsto understand structure property relationshipsM E Hawley Scienceand TechnologyDivision Los AlamosNational Laboratory Los Alamos NM hawley lanl ScanningProbe microscopes SPM are widelyrecognized aseasy to use gentle high resolution imaginginstruments which areparticularly wellsuited forstudies ofnano structuredmaterials As powerfulas theseinstruments arefor obtaining atomic tonanometer resolution their truestrength hasproven tobe theirversatility especially afterthedevelopmentof intermittentcontact methods SPMs area collectionof closelyrelated sistercapabilities which allowone todirectly correlatestructure toa propertyof interestunder awide varietyimaging conditionsand operatingmodes that includes forexample variabletemperature liquid state and magicor electricalfields In thistalk I willdescribe severalof thesetechniques including scanningtunneling microscopy magic forcemicroscopy and phaseimaging withexamples thatwill illustratesome ofSPMs uniqueapplications to the understandingthe roleof structureand fabricationparameters influenceon properties Nanomechanical and tribological characterizationof nanoposite materials ThorstenStaedler Srikanth Vadali and XinJiang Institute of MaterialsEngineering University ofSiegen Paul Bonatz Str 9 11 57076Siegen Germany Dueto theiroutstanding mechanical properties diamond films areideal candidatesfor manycutting andmachining applications However industrial applicationsof thesefilms arelimited due to pooradhesion Two mainreasons causingthis pooradhesion which are basedon the extrinsicphysical andchemical properties of diamond can beidentified High mechanicalstresses inducedby adifference of the thermalexpansion coefficientbetween thediamondfilmandthe substrate as well asa catalyticeffect incase ofmetallic substratescontaining iron cobalt and nickelthat in binationwith amethane atmosphereduring deposition leads tosoot formation One optionto overethese difficultiesis toprovide aninterfacial layerthat actsas adhesionlayer aswell asbarrier layerto preventthe catalyticeffect of thesubstrateelements Even thoughsome suessfulexamples exist this approachusually requiresa timeconsuming andexpensive multi step process In thispaper the synthesisof nanocrystallinediamond carbide positefilms witha positionalgradient willbe reported Focusing onthe exampleof diamond SiC thepossibility tocreate agradient layerranging from SiCtodiamond willbe shown One crucialfeature of the carbide diamond gradientnanoposite interlayerapproach is that itallows acontinuous variationbetween carbideand diamondphase duringgrowth For thisreason theexact characteristicsof thispositional variation linear orother is animportant optimizationparameter To feedan appropriatemodeling the mechanicalproperties such as hardnessand Young s modulusare needed In orderto getaess tothis informationscanning nanoindentationwas chosen After ashort introductionto thetesting methodand itsrequirements in ordertoget quantitativemechanical materialspropertiesof the positesof interest the resultsof nanoindentationtesting alongwith firsttribological testresults willbe presented Carbon based1 2 and3 bulk dimensional nano and nanopositematerials from synthesisto functionX Jiang M Eggers Y Qin N G Shang T Staedler J H Xia Institute of MaterialsEngineering University ofSiegen Paul Bonatz Str 9 11 57072Siegen Germany Tel 492717402966 Fax 492717402442 The synthesisof a variety of carbon structures nanosheets cones andnanotubes on ironwire substrateswas suessfullyrealized bymicrowave plasmaenhanced andconventional chemicalvapour depositiondeposition ina hydrocarbonand hydrogen containing atmosphere The morphologyaswell asthemicrostructure ofthose carbonnanostructures wasinvestigated byscanning electron microscopy transmission electronmicroscopy energy dispersivex ray and Ramanspectroscopy Direct correlationsbetween appliedprocess parametersandstructuremorphology have been observed These andother carbonnanostructures werethen mixedinto metal polymer andcement matrix forming bulkpositematerialswith enhancedphysical and mechanicalproperties III Nitride quantummaterials andnano structures fornew generationlight emittingdevices ZheChuanFENG 馮哲川教授台灣大學光電所暨電機系 Institute ofPhotonics andOptoelectronicsii HRXRD fine structures and T varied PLin InGaN MQWs iii Quantum dot likestructuresandQuantum confinedStokes effect QCSE within InGaN QWs iv Phase separation in InGaN v Origins andmechanisms ofintense luminescencefrom InGaN GaNMQWs vi FTIRvii Combined PL Raman onIII Ns andmulti phonon resonance viii Multi technique characterizationof MOCVD grown GaNonSisubstrates It sexpectedthat theexploration orsolving theseproblems maypromote theresearch anddevelopment fornew generationlightemittingdevices Determination of the chirality ofcarbonnanotubes Lu Chang QinW M Keck Laboratoryfor AtomicImaging andManipulation Department of Physics andAstronomy andCurriculum inApplied andMaterials Sciences University ofNorth Carolinaat ChapelHill NC27599 3255 USA E mail lcqin physics unc Theatomic structure of a carbonnanotubecan bedefined byspecifying itschirality orchiral indices u v that specifyits perimetervector chiral vector with whichthe diameterand helicityare alsodetermined Since thepropertiesof acarbonnanotube isvery sensitive to itschirality precise measurementof the chiralityofcarbonnanotubesis oftenrequired forunderstanding andexploitation of the mostfundamental structure property relationships The fineelectron beamavailable ina moderntransmissionelectronmicroscope TEM offers aunique andpowerful probeto reveal the chiralityof individualnanotubes The assignmentof the chiral indices u v of acarbonnanotubefrom itselectron diffractionpattern is approachedfromtherelationship betweenthe electron diffraction intensity distribution andthe chiral indices u v I willpresent twoplementary methodsfor obtainingthechiralindices u v ofacarbonnanotubesfrom itselectrondiffractionpatterns The firstmethod isto obtainthechiralindices u v by readingdirectly theintensitydistributiononthethree principal layer lines l1 l2 and l3 which haveintensities proportionalthe squareof Besselfunctions oforders v u andu v 21 dR JIv l 22 dR JIu l and23 dR JIv ul The secondmethod istousethe ratioof theindices 2 2 2112D D DDu v in whichD1and D2are thespacings ofprincipallayerlines l1and l2 respectively Examples ofusing thesemethods willalso bepresented toillustrate thedetermination ofchiralindicesof isolatedindividual single walled carbonnanotubes aswellasmultiwalled carbonnanotubes Core shell ironnanoparticles synthesis nanostructures magism and their applicationsYou Qiang Department ofPhysics University ofIdaho Moscow ID83844 0903Nanoparticles havegained increasedattention recentlyfor biomedicaland environmentalapplications Biopatible magianoparticles MNPs have beenfound promisingin applicationsfor tagging imaging drug delivery sensing andseparationinrecentyears Most magic particles orbeads currentlyused inthose applicationsarebasedon iron oxides withvery lowspecific magic moments of 30emu g In this presentation I reportroom temperature synthesisof noveliron ironoxidecore shell MNPsusing anewly developednanocluster source Monodispersive ironMNPs withsize ofdiameters from1to100nm areproduced ina clustersource chamberand thentransmitted into the reactionchamber wherea smallpartial pressureof O2ispresentsothat the ironMNPs arecoated withuniform ironoxide shell These shellsact aspassivation layerspreventing furtheroxidation ofthe coresupon subsequentor continuedexposure toair The b Fe corewith magiteshells wasobserved byXRD andHRTEM The core shell nanoclusters are superparamagicat roomtemperature forsizes lessthan15nm and thenbee ferromagicwhen thecluster sizeincreases The specificmagic momentof core shell MNPsis sizedependent and increasesrapidly fromabout80emu gatthe size of3nm toover200emu g upto the sizeof100nm The useof highmagicmomentMNPs candramatically enhancethe contrastfor MRI reduce theconcentration ofmagicparticleneeds forcell separation or makedrug deliverypossible withmuch lowermagic fieldgradients For examples 1 MNPs incancer treatment 2 MNP Enzyme conjugatesfor environmentalapplication and3 clean energyfor future driving carby burningmetal MNPfuel Research supportedby NIH DOE BES and NSF EPSCoR Dipolar interactioninmagiano clusters systemsX X Zhang Department ofPhysics Chemistry andInstitute ofNano Scienceand Technology The Hong Kong University of Scienceand Technology Clear WaterBay Kowloon HongKongWe havestudied thenano cluster systems such asCo SiO2and FeAgwith thelow temperaturemagic measurementsto observethe memoryeffect It has beenreportedthatinthe nanoparticlessystems also inthe non continue multilayers when theconcentration ofthe particlesis high the dipole dipole interactionsbee strongenough tolead toa low temperature spin glass phase which wasevidenced byobservation ofaging effectand memoryeffect the characteristicpropertiesofthe spin glasses The nano particles areoxide andnitride inthe mostof studies Magic studiesonthenano particles indicatedthat someofthe spin glass like phenomenaobserved couldbe dueto theexistence ofspin glass like shellssurrounding theferrimagic cores The core shell structuresofthenanoparticles havebeen demonstratedbytheTEM observations Therefore a questionremains tobe answeredisthat thespin glass phenomenaobserved innanoparticles reallyoriginated fromthe dipole dipole interactions We wanttousethe magiano cluster systemsto clarifythis question Micromechanics based mago elastic constitutivemodeling ofmagostrictive positesLizhi SunDepartmentofCivil Environmental Engineering and Departmentof ChemicalEngineering MaterialsScienceEngineering University ofCalifornia Irvine CA92697 2175 USA Mago elastic behavioris investigatedfor two phase positescontaining magostrictiveparticles underboth magic andmechanical loading The modifiedGreen s functionsare derived for threesituations a magic field causedby alocal magization a displacementfield causedby alocal bodyforce anda displacementfield causedbyalocally prescribedeigenstrain Based onthese functions an explicitsolution isderivedfortwo magicparticles embedded intheinfinite mediumunder externalmagic andmechanicalloading Composites containingspherical magicparticles ofthe samesize are considered fortwo kindsof microstructures With chain structured posites particle interactionsinthesame chainareconsideredandatransversely isotropiceffective elasticityis obtained In the random posite pair wise particleinteractions areintegrated fromall possiblepositions andan isotropiceffective propertyis reached Effective magostrictionand field dependent effectiveelasticity areinvestigated It isseen thatthe chain structured positeis moresensitivetothe magic field than therandom posite The effectiveshear modulusofthechain structured positerapidly increaseswith the magic field while thatfortherandompositedecreases Field induced martensitic transformation inmagic shapememory alloyGuang HengWu S Y Yu G D Liu Z H Liu and J L Chen BeijingNational Laboratoryfor CondensedMatter Physics InstituteofPhysics Chinese Academyof Sciences Beijing100080 P R China Strongmagicfield induced martensitic transformation effecthas beeninvestigated inferromagic shapememory alloy FSMA of NiMn In Sb Ga It providesa verygood objectsystem torevealtherelationship betweenlattice structuraltransition martensitictransformation and magicstructure transitionin FSMAmaterials Here wereport aseries ofphysical datameasured bymagicandelectrical methodsin singlecrystalline samples The materialshows apparentfield induced martensitictransformation aompanyingbyamagic structuraltransition between ferromagicand partialantiferromagic ones On theother hand themagicstructure exhibitsso stronginfluence tolattice variationthatthemartensitictransformationwas forcedto oureven phenomenallyin anopposite thermaldynamic directionand thusthe transformationbecame dramaticallycontrollable Based onthese results many applications suchasmagicfield controllable shapememory magic refrigerationand largemagoresistance canbeexpected Doped semiconductornanoparticles ferromagism and UV photoluminescenceabove roomtemperature YouQiangDepartmentofPhysics UniversityofIdaho Moscow ID8384 4 0903Diluted magicsemiconductor DMS of doped ZnO isof greatinterest tocurrent researchduetoits widevarietyofapplications inspintronics andsensors We synthesizedTi V Co orNi doped ZnO nanoclusters usinga thirdgeneration nanoclustersource thatutilize abination ofmagron sputteringand gas aggregation technique High resolution TEMimages showthatthenanoclusters aremonodispersive witha nanocrystallinesize 10nm XRD patternsare identicaltothebulk ZnOwurtzite structure XPS detectedthe dopant elements which areuniformly distributedin dopednanoclusters High resolution XPSshowed oxidationstates ofdopant Tiin 4 and Coin 2with isovalance while Vin 4and 5 and Niin 2and 3with mixed valances These analysesindicate thatdopantelementsdo notexist asindependent aggregatesbut areincorporated intothe ZnOstructure All thedoped ZnOnanoclustersareferromagic aboveroomtemperature Magic momentsof Niand V doped ZnO 1 5 B or3 5 B perdopant atom are much largerthanTi orCo dopedZnO clusters 0 2 B or0 6 B perdopant atom Double exchangeinteractions duetothemixedvalancestates are the reasonthat Nior V dopedZnOclusters havemuchlargermagic momentsthantheTi orCo doped clusters Both magicandUVoptical propertiesof dopedZnOnanoclustersare dopantconcentration dependent Applications ofIsing modelin fieldsof materialsphysics J M Liu 刘俊明 Laboratory ofSolid StateMicrostructures Nanjing University Nanjing210093 China InternationalCenter forMaterials Physics Chinese Academyof Sciences Shenyang China Email liujm nju Web pld nju TheIsing modelas oneofthesimplest andpowerful modelsin statisticalphysics hasbeen employedextensively toillustrate thephysics associatedwithahuge numberof phenomenain naturaland socialsciences In thistalk I shallbriefly mention this modelinthelanguage ofmagism