纳米科技全英文ppt

TheEraofNanotechnologyRichardPhillipsFeynman•RichardPhillipsFeynman(May11,1918–February15,1988)wasanAmericanphysicistknownforhisworkinthepathintegralformulationofquantummechanics,thetheoryofquantumelectrodynamicsandthephysicsofthesuperfluidityofsupercooledliquidhelium,aswellasinparticlephysics(heproposedthepartonmodel).Forhiscontributionstothedevelopmentofquantumelectrodynamics,Feynman,jointlywithJulianSchwinger,receivedtheNobelPrizeinPhysicsin1965RichardFeynman•FromtheStoneAge,humansfromthegroundtothetipofthearrowallthechiplithographytechniques,orwiththeintegrationofslashingthenumberofone-time•Whycannotwestartfromanotherangle,fromsinglemoleculesorevenatomsbegintobeassembledtomeetourrequirements?Hesaid:Atleastinmyview,thelawsofphysicsdonotruleoutcreatingthingsatombyatompotentialRichardFeynman•从石器时代开始，人类从磨尖箭头到光刻芯片的所有技术，都与一次性地削去或者融合数以亿计的原子以便把物质做成有用的形态有关。Feynman质问道，为什么我们不可以从另外一个角度出发，从单个的分子甚至原子开始进行组装，以达到我们的要求？ThequestionofRichardFeynmanThestoneimplementsThecoreplateAbriefintroductiontothenanotechnologyNanotechnologyisthestudyofmanipulatingmatteronanatomicandmolecularscale.Generally,nanotechnologydealswithstructuressizedbetween1to100nanometreinatleastonedimension,andinvolvesdevelopingmaterialsordeviceswithinthatsize.Quantummechenicaleffectsareveryimportantatthisscale,whichisinthequantumrealm.Nanotechnologyisverydiverse,rangingfromextensionsofconventionaldevicephysicstocompletelynewapproachesbaseduponmolecularself-assembly,fromdevelopingnewmarerialswithdimensionsonthenanoscaletoinvestigatingwhetherwecandirectlycontrolmatteronthatomicscale.MicroscopeMicroscope•Amicroscopeisaninstrumentusedtoseeobjectstoosmallforthenakedeye.Thescienceofinvestigatingsmallobjectsusingsuchaninstrumentiscalledmicroscopy.Microscopicmeansinvisibletotheeyeunlessaidedbyamicroscope.•Therearemanytypesofmicroscopes,themostcommonandfirsttobeinventedistheopticalmicroscopewhichuseslighttoimagethesample.Othermajortypesofmicroscopesaretheelectronmicroscope(boththetransmissionelectronmicroscopeandthescanningelectronmicroscope)andthevarioustypesofscanningprobemicroscope.electronmicroscope•TEM(TransmissionElectronMicroscopy)isamicroscopytechniquewherebyabeamofelectronsistransmittedthroughanultrathinspecimen,interactingwiththespecimenasitpassesthrough.Animageisformedfromtheinteractionoftheelectronstransmittedthroughthespecimen;theimageismagnifiedandfocusedontoanimagingdevice,suchasafluorescentscreen,onalayerofphotographicfilm,ortobedetectedbyasensorsuchasaCCDcamera.•AFleaasimagedusinganelectronmicroscope•AdustmitedanderQuantumMechanicsQuantumMechanics•Quantummechanics,alsoknownasquantumphysicsorquantumtheory,isabranchofphysicsprovidingamathematicaldescriptionofthedualparticle-likeandwave-likebehaviourandinteractionofmatterandenergy.•Quantummechanicsdepartsfromclassicalmechanicsprimarilyattheatomicandsub-atomicscales,theso-calledquantumrealm.Inspecialcasessomequantummechanicalprocessesaremacroscopic,buttheseemergeonlyatextremelyloworextremelyhighenergiesortemperatures.Scanningelectronmicroscope•SEM(SEM)scanningelectronmicroscopeisatypeofmicroscopethatimagesasamplebyscanningitwithahigh-energybeamofelectronsinarasterscanpattern.Theelectronsinteractwiththeatomsthatmakeupthesampleproducingsignalsthatcontaininformationaboutthesample'ssurfacetopography,composition,andotherpropertiessuchaselectricalconductivity.•ThetypesofsignalsproducedbyanSEMincludesecondaryelectrons,back-scatteredelectrons(BSE),characteristicX-rays,light(cathodoluminescence),Scanningelectronmicroscope•specimencurrentandtransmittedelectrons.SecondaryelectrondetectorsarecommoninallSEMs,butitisrarethatasinglemachinewouldhavedetectorsforallpossiblesignals.Thesignalsresultfrominteractionsoftheelectronbeamwithatomsatornearthesurfaceofthesample.Inthemostcommonorstandarddetectionmode,secondaryelectronimagingorSEI,theSEMcanproduceveryhigh-resolutionimagesofasamplesurface,revealingdetailsaboutlessthan1to5nminsize.Duetotheverynarrowelectronbeam,SEMmicrographshavealargedepthoffieldyieldingacharacteristicthree-dimensionalappearanceusefulforunderstandingthesurfacestructureofasample.Thisisexemplifiedbythemicrographofpollenshowntotheright.Awiderangeofmagnificationsispossible,STMthebirthofclusterscienceandtheinventionofthescanningtunnelingmicroscope(STM).Thisdevelopmentledtothediscoveryoffullerenesin1985andcarbonnanotubesafewyearslater.Inanotherdevelopment,thesynthesisandpropertiesofsemiconductornanocrystalswasstudied;thisledtoafastincreasingnumberofmetalandmetaloxidenanoparticlesandquantumdots.TheatomicforcemicroscopewasinventedsixyearsaftertheSTMwasinvented.In2000,theUnitedStatesNationalNanotechnologyInitiativewasfoundedtocoordinateFederalnanotechnologyresearchanddevelopmentandisevaluatedbythePresident'sCouncilofAdvisorsonScienceandTechnology.ProcedureofSTM•First,avoltagebiasisappliedandthetipisbroughtclosetothesamplebysomecoarsesample-to-tipcontrol,whichisturnedoffwhenthetipandsamplearesufficientlyclose.Atcloserange,finecontrolofthetipinallthreedimensionswhennearthesampleistypicallypiezoelectric,maintai