透射電子顯微鏡TransmissionElectronMicroscopy當(dāng)代分析措施與技術(shù)目錄Contents透射電子顯微鏡21歷史History2原理Background3構(gòu)造Components4制備Preparation5應(yīng)用Application歷史History最初研究Initialdevelopment透射電子顯微鏡3ErnstAbbe(*23.Januar1840;?14.Januar1905),deutscherAstronom對(duì)物體細(xì)節(jié)的分辨率受到用于成像的光波波長(zhǎng)的限制Theabilitytoresolvedetailinanobjectwaslimitedapproximatelybythewavelengthofthelightusedinimaging光學(xué)顯微鏡分辨率僅在微米級(jí)limitstheresolutionofanopticalmicroscopetoafewhundrednanometersAugustK?hler(March4,1866–March12,1948),GermanyPhysicistMoritzvonRohr(4April1868–20June1940),GermanyPhysicistJuliusPlücker(16July1801–22May1868)GermanmathematicianandphysicistFerdinandBraun(4April1868–20June1940),GermanyPhysicist185818971891192619281931JuliusPlücker磁場(chǎng)可使陰極射線彎曲Thedeflectionof"cathoderays"(electrons)waspossiblebytheuseofmagneticfieldsRiecke使用磁場(chǎng)能夠使陰極射線聚焦Thecathoderayscouldbefocusedbymagneticfields,allowingforsimplelensdesignsAugustK?hlerandMoritzRohr研制出能夠?qū)O限辨別率提升約一倍的紫外光顯微鏡Developmentsintoultraviolet(UV)microscopesallowedforanincreaseinresolvingpowerofaboutafactoroftwoFerdinandBraun陰極射線示波器Built

primitivecathoderayoscilloscopes(CROs)intendedasameasurementdeviceAdolfMatthias&MaxKnoll考慮了透鏡設(shè)計(jì)和示波器的列排列，研制能夠用于產(chǎn)生低放大倍數(shù)（接近1:1）的電子光學(xué)原件AttemptedtoobtaintheparametersthatcouldbeoptimizedtoallowforconstructionofbetterCROs,aswellasthedevelopmentofelectronopticalcomponentswhichcouldbeusedtogeneratelowmagnification(nearly1:1)imagesHansBusch制鏡者方程在合適的條件下能夠用于電子射線Thelensmaker'sequationcouldbeapplicabletoelectronsunderappropriateassumptionsMaxKnollGroup成功的產(chǎn)生了在陽(yáng)極光圈上放置的網(wǎng)格的電子放大圖像——第一臺(tái)電子顯微鏡SuccessfullygeneratedmagnifiedimagesofmeshgridsplacedovertheanodeapertureArguablythefirstelectronmicroscope1LouisdeBroglie

(15

August1892–19

March1987),FranchPhysicistAwardedNobelPrizeinPhysics(1929)LouisdeBroglie,1927電子作為物質(zhì)粒子的波動(dòng)特征Thewavenatureofelectronshadnotbeenfullyrealizeduntilthepublicationofthe

DeBrogliehypothesis

in1927電子波的波長(zhǎng)比光波波長(zhǎng)小了若干數(shù)量級(jí)，理論上允許人們觀察原子尺度的物質(zhì)TheDeBrogliewavelengthofelectronswasmanyordersofmagnitudesmallerthanthatforlight,theoreticallyallowingforimagingatatomicscales歷史History辨別率的提升ImprovingResolution透射電子顯微鏡4MaxKnoll&ErnstRuska1932建造一種新的電子顯微鏡以直接觀察插入顯微鏡的樣品Constructedanewelectronmicroscopefordirectimagingofspecimens

insertedintothemicroscope1933通過(guò)對(duì)棉纖維成像正式地證明了TEM的高分辨率ByusingimagesofcottonfibersdemonstratedthehighresolutionofTEM第一臺(tái)商用TEMThefirstcommercialelectronmicroscope

wasinstalledinthePhysicsdepartmentofIGFarben-Werke1936改進(jìn)TEM的成像效果，尤其是對(duì)生物樣品的成像TheimprovementofTEMimagingproperties,particularlywithregardtobiologicalspecimensThefirstpracticalTEM,originallyinstalledatIGFarben-WerkeandnowondisplayattheDeutschesMuseuminMunich,Germany1歷史History進(jìn)一步研究FurtherResearch透射電子顯微鏡51AfterWorldWarⅡErnstRuskaatSIMENS生產(chǎn)了第一臺(tái)能夠放大十萬(wàn)倍的顯微鏡Producedthefirstmicroscopewith100kmagnification1942第一屆電子顯微鏡國(guó)際會(huì)議(Delft)Thefirstinternationalconferenceinelectronmicroscopy1950InParis1954

InLondon1970AlbertCrewe(ChicagoUniversity,USA)發(fā)明了場(chǎng)發(fā)射槍，添加了高質(zhì)量的物鏡，發(fā)明了現(xiàn)代的掃描透射電子顯微鏡Developedthefieldemissiongun

andaddedahighqualityobjectivelenstocreatethemodernSTEM(ScanningTransmissionElectronMicroscopy)ASTEMequippedwitha3rd-ordersphericalaberrationcorrector目錄Contents透射電子顯微鏡61歷史History2原理Background3構(gòu)造Components4制備Preparation5應(yīng)用Application原理Background電子Electron透射電子顯微鏡72

光學(xué)顯微鏡所能達(dá)成的最大辨別率受到如下條件的限制Themaximumresolutionthatonecanobtainwithalightmicroscopehasbeenlimitedby照射在樣品上的光子波長(zhǎng)λthewavelengthofthephotonsthatarebeingusedtoprobethesampleλ光學(xué)系統(tǒng)的數(shù)值孔徑，NAthenumericalapertureofthesystemNA相對(duì)論修正Anadditionalcorrectiontoaccountforrelativisticeffects透射出的電子束包具有電子強(qiáng)度、相位、以及周期性的信息，這些信息將被用于成像Thetransmittedbeamcontainsinformationaboutelectrondensity,phaseandperiodicity.Thisbeamisusedtoformanimage原理Background電子源SourceFormation透射電子顯微鏡82

材料MaterialsTungstenorLaB6形制ShapesHairpin-stylefilamentSmallspike-shapedfilament

HairpinstyletungstenfilamentSinglecrystalLaB6filament高壓電源highvoltagesource(typically~100–300kV)熱電子發(fā)射

或場(chǎng)電子發(fā)射thermionicorfieldelectronemission兩種物理現(xiàn)象TwoPhysicalEffects運(yùn)動(dòng)的電子在磁場(chǎng)中將會(huì)根據(jù)右手定則受到洛倫茲力的作用Theinteractionofelectronswithamagneticfieldwillcauseelectronstomoveaccordingtothelefthandrule使用磁場(chǎng)能夠形成不同聚焦能力的磁透鏡Theuseofmagneticfieldsallowsfortheformationofamagneticlensofvariablefocusingpower原理Background電子光學(xué)設(shè)備與成像設(shè)備Optical&Display透射電子顯微鏡92

透鏡Lens

電子束聚焦Beamconvergence三級(jí)透鏡Threestagesoflensing

聚焦透鏡Thecondenserlenses

物鏡Theobjectivelenses

投影透鏡Theprojectorlenses熒光屏FluorescentScreenZnS(10–100

μm)FilmsCCDLayoutofopticalcomponentsinabasicTEM目錄Contents透射電子顯微鏡101歷史History2原理Background3構(gòu)造Components4制備Preparation5應(yīng)用Application構(gòu)造Components真空系統(tǒng)VacuumSystem(No.11)透射電子顯微鏡113

作用Effects在陰極和地之間加以很高的電壓，而不擊穿空氣產(chǎn)生電弧Theallowanceforthevoltagedifferencebetweenthecathodeandthegroundwithoutgeneratinganarc將電子和空氣原子的撞擊頻率減小到能夠忽視的量級(jí)Toreducethecollisionfrequencyofelectronswithgasatomstonegligiblelevels構(gòu)成Components旋片泵或隔膜泵RotaryVanePumporDiaphragmPumps低真空Settingasufficientlylowpressure渦輪分子泵或擴(kuò)散泵Turbo-molecularorDiffusionpump高真空Establishinghighvacuumlevel門閥或差動(dòng)泵GatevalvesorDifferentialpumpingaperture隔離電子槍與主腔室Isolatedthegunfromthemainchamber離子泵或吸氣材料IonpumporGettermaterialTheelectronsourceoftheTEMisatthetop,wherethelensingsystem(4,7and8)focusesthebeamonthespecimenandthenprojectsitontotheviewingscreen(10).Thebeamcontrolisontheright(13and14)構(gòu)造Components樣品臺(tái)SpecimenStage(No.6)透射電子顯微鏡123

尺寸Size直徑3.05mm的環(huán)形，其厚度和網(wǎng)格大小不不小于100微米StandardTEMgridsizesarea3.05mmdiameterring,withathicknessandmeshsizerangingfromafewto100μm內(nèi)部的網(wǎng)格區(qū)域直徑約2.5mmThesampleisplacedontotheinnermeshedareahavingdiameterofapproximately2.5mm材料Materials:Cu,Mo,Au,Pt設(shè)計(jì)Design側(cè)入式theSide-entryversion頂入式theTopentryversionTheelectronsourceoftheTEMisatthetop,wherethelensingsystem(4,7and8)focusesthebeamonthespecimenandthenprojectsitontotheviewingscreen(10).Thebeamcontrolisontheright(13and14)構(gòu)造Components電子槍ElectronGun(No.2)透射電子顯微鏡133

構(gòu)成Consistance燈絲、偏置電路、韋乃特陰極、陽(yáng)極theFilament,aBiasingcircuit,aWehneltcap,andanExtractionanode材料Materials:Cu,Mo,Au,Pt設(shè)計(jì)Design側(cè)入式theSide-entryversion頂入式theTopentryversionTheelectronsourceoftheTEMisatthetop,wherethelensingsystem(4,7and8)focusesthebeamonthespecimenandthenprojectsitontotheviewingscreen(10).Thebeamcontrolisontheright(13and14)構(gòu)造Components電子透鏡ElectronLens(No.4)透射電子顯微鏡143

構(gòu)成Consistance外殼、磁線圈、磁極、極靴、外部控制電路theyoke,themagneticcoil,thepoles,thepolepiece,andtheexternalcontrolcircuitryTheelectronsourceoftheTEMisatthetop,wherethelensingsystem(4,7and8)focusesthebeamonthespecimenandthenprojectsitontotheviewingscreen(10).Thebeamcontrolisontheright(13and14)目錄Contents透射電子顯微鏡151歷史History2原理Background3構(gòu)造Components4制備Preparation5應(yīng)用Application制備Preparation透射電子顯微鏡164

要求Requirement薄片在納米尺度TEMspecimensarerequiredtobeatmosthundredsofnanometersthick措施Methods切片加工法TissueSectioning染色加工法SampleStaining機(jī)械加工法MechanicalMilling化學(xué)腐蝕法ChemicalEtching離子刻蝕法IonEtching復(fù)制法ReplicationChemicalEtchingReplicationIonEtchingMechanicalMillingSampleStaningTissueSectioning工具Tools玻璃或金剛石GlassorDiamonds優(yōu)勢(shì)Advantage取得薄而最低程度變形的樣本toobtainthin,minimallydeformedsamples局限Limitation對(duì)軟樣品傷害極大theheavydamageinducedinthelesssoftsamplesAdiamondknifebladeusedforcuttingultrathinsections(typically70to350nm)fortransmissionelectronmicroscopy工具Tools重金屬HeavyMental(Os,Pb,Au,U)優(yōu)勢(shì)Advantage經(jīng)過(guò)著色提升吸收光線來(lái)增強(qiáng)觀察細(xì)節(jié)Enhancethedetailsinlightmicroscopesamplesstains