PrinciplesofMaterialsCharacterizationandMetrology
KannanM.Krishnan
UniversityofWashington,Seattle
GreatClarendonStreet,Oxford,OX26DP, UnitedKingdom
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To Amma, Appa, MN, andmystudents—past,present,andfuture
Preface
Materialsscienceandengineering(MSE)isamultidisciplinaryfield,impacting everyaspectofourtechnologicalsocietytoday.AttheheartofMSEisunderstandingtherelationshipbetweenstructureandpropertiesofmaterials.Infact, itisnowwellestablishedthat,byoptimizingcompositionandstructureranging fromthemacroscopictoatomicdimensions,thepropertiesofmaterialscanbenot onlywellcontrolledbutalsotailoredforanyspecificapplication.Inthisendeavor, materialscharacterization and analysis involvingarangeof diffraction, imaging, and spectroscopy methods,atrelevantlengthscales,hasenabledthestructure–property–processing–performancetetrahedronthatepitomizesthefield.
Traditionally,an undergraduate curriculuminMSEemphasizesthepractical applicationofopticalmicroscopyandspectroscopy,impartsaworkingknowledge ofX-raydiffractionand,whereresourcesareavailable,scanningandtransmission electronmicroscopy,andatomicforcemicroscopy.However,recentadvancesin developingmaterialsforawiderangeofapplications,emphasizingatomic-scale tailoringofmicrostructureandexploitingsize-dependentproperties,requirean interdisciplinaryapproachtomaterialsdevelopmentwhereajudicioususeof availablecharacterizationmethodsbecomesimportant.Thisrequiresacoherent discussionoftheunderlying physicalprinciples ofmaterialscharacterizationand metrologyusingthewiderangeofelectrons,photons,ions,neutrons,andscanning probes.
Followingabroadintroduction(§1),thisbooklaysthefoundationsofcharacterization,analysis,andmetrologyandbuildsonconceptsthatshouldbefamiliar toanupper-divisionstudentinanybranchofscienceorengineering.Starting withatomicstructure,wedevelopspectroscopymethodsbasedonintra-atomic electronictransitions(§2),followedbybondingandtheelectronicstructure ofmoleculesandsolidsmotivatinganumberofspectroscopymethods(§3). Wethendiscusstheperiodicarrangementofatomsanddevelopprinciplesof crystallography(§4),whichleadstoanintroductiontodiffractioninbothrealand reciprocalspace.Next,weaddressdifferentprobesandpresentrelevantdetails ofthegenerationanduseofphotons,electrons,ions,neutrons,andscanning probes(§5),followedbyapresentationofion-basedscatteringmethods(§5). Aconciseintroductiontooptics,opticalmicroscopy,polarizationoflight,and ellipsometryfollows(§6).Thesecondpartofthebookincludesacomprehensive discussionofdiffractionandimagingmethodsthatemphasizetechniqueswidely usedinthecharacterizationandanalysisofmaterials.ThisincludesX-ray(§7), electron(§8),andneutron(§8)diffraction,aswellastransmissionandanalytical electron(§9),scanningelectron(§10),andscanningprobe(§11)microscopies. Throughoutthetext,thecharacterizationtechniquesarealsousedtointroduce
andillustratefundamentalpropertiesandmaterialsscienceconceptsencountered inawiderangeofmaterials.Thebookisgenerouslyillustratedthroughoutwith figures,datatables,comparisonbetweenrelatedmethods,workedexamples,and concludes(§12)withthreeuniqueandcomprehensivetablessummarizingthe salientpointsofallthespectroscopy,diffraction,andimagingmethodspresented.
Tokeeptheoverallextentofthebooktoamanageablelength,Ihavemainly emphasized probe-basedtechniques.Othermethods,suchasthermalcharacterizationandpropertymeasurements,includingmechanicaltesting,aredeliberately notincluded.However,Idoincludenumerousapplicationsofmaterialsand structuresinfieldsrangingfromscience,technology,art,andbiology.Each chapteralsoincludesanumberofworkedexamplestohelptietogetherthe conceptsintroducedtherein,anextensivesetoftest-your-knowledgequestions tohelpreadersconsolidateunderstandingofthesubjectmatterbasedonthetext, problemsetstofurtherdeepenlearning,asummaryhighlightingthekeyconcepts andideaspresentedineachchapter,andanextensivebibliographyforfurther reading.
Whilespecializedbooksdoexistformostofthetechniquesdiscussedhere, includingencyclopediasofmaterialscharacterization,acoherenttextbookon materialscharacterizationandmetrologyattheundergraduateorearlygraduate level,emphasizingfundamentalphysicalprinciples,suchasthisone,isboth lackingandhighlydesirable.Combiningdiscussionsoftheunderlyingprinciples withpracticalexamples,anddetailedsetsofexercises,thisbookwillideallyserve asatextfora year-longcourse attheundergraduateand/orearlygraduatelevel. CompletionofsuchacourseshouldgivestudentsanentryintotheinterdisciplinaryfieldofMaterialsScienceandEngineering,andasolidfoundationin characterizationandanalysismethods,withtheabilitytoselectandapplythe appropriatetechniqueforanycharacterizationproblemathand.Alternatively,the bookcanbeadaptedtoa semester-lengthcourse,takingamoretraditionalapproach bydevotingaboutfiveweekseachtospectroscopy(Chapters2,3,9,and10), diffraction(Chapters4,7,and8),andimaging(Chapters6,9–11).Ifoneis furtherconstrainedintimetoa 10-weekquarterorterm,asinmanyUSuniversities, andwhichisthecaseforthecourseIhavebeenteaching(syllabusavailableon request)formanyyearsatUW—whereUGstudentstakethiscourseafterprior exposuretoX-raydiffractionandtheelectronicstructureofsolids—thisbook maybeadoptedbyteaching,selectively,theessentialconceptsofChapters1–6at theapproximatepaceofonechapterperweek,andinthelastfourweeks,covering scanningelectron(Chapter10)andscanningprobe(Chapter11)microscopies. Assigningtermpapertopicsforself-study,involvingmorespecializedtechniques andtheirapplications,includingtransmissionelectronmicroscopy(Chapter9), wouldfurtherstrengthenstudentlearning.
ForthosestudentsfromdifferentdisciplinesotherthanMSE,thisbook provideswhattheywillessentiallyneedtoknowinmaterialscharacterization, includingadditionalbackground,atanearlystageoftheirstudy.Overall,this bookisexpectedtopotentiallyhaveawidereadershipandacademicrelevance
forteachingacourseoncharacterization,analysis,andmetrology,acrossmultiple disciplinesofengineering,physics,chemistry,geology,biology,artconservation, etc.Theexamplesinthebookareselectedtoreinforcethisbreadthofdisciplines. Finally,eventhoughthistextbookistailoredfortheteachingofupper-division undergraduateorearly-stagegraduatestudents,itisalsowrittenforself-studyby experiencedresearchers,includingthoseinindustry,whorealizethat,todelivera program/productsatisfactorily,theyneedtoknowmoreaboutthemicrostructure oftheirmaterialsthantheycurrentlydo!
Inwritingthisbook,Ibenefittedfromdiscussionswithnumerouscolleagues andteacherswhogenerouslysharedtheirknowledgeinmultipledisciplines withmeoverthelastfourdecades.Someofthemalsoreviewedsectionsof thismanuscriptatvariousstagesofdevelopment.Alphabeticallytheyinclude: S.D.Bader,P.Blomqvist,S.Brück,J.N.Chapman,D.E.Cox,U.Dahmen, C.J.Echer,R.Egerton,M.Farle,P.J.Fischer,E.E.Fullerton,C.Hetherington,F.Hofer,W.Grogger,R.Gronsky,R.Kilaas,C.A.Lucas,R.K.Mishra, Y.Murakami,C.Nelson,S.Paciornik,S.J.Pennycook,L.Rabenberg,P.Rez, D.Shindo,I.K.Schuller,S.G.E.teVelthuis,N.Thangaraj,S.Thevuthasan, G.Thomas,M.Varela,D.O.Welch,T.Wen,andT.Young.Ialsoofferaspecial noteofthankstomyformerstudents,EricTeemanandRyanHufshmid,who haveindependentlycreated,fortheexercisesinthebook,asolutionmanual (availablefromOUPtothosewhoadoptthisbookforteachingacourse),and theanonymousreviewerwhoprovidedachapter-by-chapterreviewoftheentire book.Also,Ibenefittedimmenselyfrominteractionswithmanygenerationsof graduatestudentsandpost-doctoralfellowsatbothUCBandUWwho,driven bytheirowncuriosityandinterests,providedmethemotivationtolearnand applyawiderangeofcharacterizationmethodsinourresearch.Thelististoo longtoacknowledgethemindividuallyhere,butmanyoftheircontributionsare reflectedinthisbook.Finally,overthepastmanyyears,studentsofmycourse onPrinciplesofMaterialsCharacterization(MSE333)atUWhaveuseddraft chaptersofthisbookasithasevolvedovertimewithsubsequentrevisions.Their constructivefeedbackandrelentlesscriticismshavesignificantlyimprovedthe book,makingitmoreaccessibleandtailoredtostudentteachingandlearning. Iamdeeplyindebtedtoallofthepeoplementionedhere;however,Iamentirely responsibleforanyremainingomissions,errors,ormistakes,andiftheyare broughttomyattention,Iwillbemorethanhappytoaddresstheminsubsequent revisions.Thisbookhasbeenmanyyearsinthemakingandpartsofitwerewritten duringmultipleresidenciesinanumberofplaces.Iamparticularlybeholden totheWhitelyCenter,anidyllicwritingretreatatFridayHarbor,theBrahm PrakashVisitingProfessorshipattheIndianInstituteofScience,Bangalore,the JSPSSeniorFellowshipattheUniversityofTohoku,andtheHumboldtCareer ResearchAwardattheUniversityofDuisburg-Essen,allofwhichprovidedthe rightatmospheretomakesubstantialprogressinwritingthisbook.
KannanM.Krishnan
Seattle,August2020
1.IntroductiontoMaterialsCharacterization,Analysis,andMetrology 1
1.1Microstructure,Characterization,andtheMaterialsEngineeringTetrahedron2 1.2ExamplesofCharacterizationandAnalysis7
1.2.1Ni-BasedSuperalloys:UltrahighTemperatureMaterialsforJetEngines8
1.2.2UnravelingtheStructureofDeoxyribonucleicAcid(DNA)10
1.2.3CharacterizingaPicassoPaintingRevealsHiddenSecrets12
1.2.4FailureAnalysis:Metallurgyofthe RMSTitanic 13
1.2.5BeneathOurFeet:MicrostructureofRocksandMinerals15
1.2.6CeramicMaterials:SinteringandGrainBoundaryPhases17
1.2.7MicrostructureandthePropertiesofMaterials:AnEngineeringExample20
1.3.1ProbesandSignals 22
1.3.2ProbesBasedontheElectromagneticSpectrumandTheirAttributes22
1.3.3Wave–ParticleDuality
1.3.4NatureandPropagationofElectromagneticWaves27
1.3.5InteractionsofProbeswithMatterandCriteriaforTechniqueSelection29 1.4MethodsofCharacterization:Spectroscopy,Diffraction,andImaging34
1.4.1Spectroscopy:Absorption,Emission,andTransitionProcesses34
1.4.2ScatteringandDiffraction
1.4.3ImagingandMicroscopy
1.4.4DigitalImaging
1.4.5 InSitu MethodsacrossSpatialandTemporalScales56
2.2.1Bohr–Rutherford–SommerfeldModel69 2.2.2QuantumMechanicalModel70
2.3AtomicSpectra:Transitions,Emissions,andSecondaryProcesses78
2.3.1DipoleSelectionRulesandAllowedTransitionsofElectronsinAtoms78
2.3.2CharacteristicX-RayEmissionsandtheirNomenclature85
2.3.3Non-RadiativeAugerElectronEmission91
2.3.4ElectronPhotoemission
2.4X-RaysasProbes:GenerationandTransmissionofX-Rays97
2.4.1LaboratorySourcesandMethodsofX-RayGeneration98
2.4.2X-RayAbsorptionandFiltering102
2.4.3SynchrotronSourcesofX-RayRadiation105
2.5X-RaysasSignals:Core-LevelSpectroscopywithX-Rays107
2.5.1InstrumentationforDetectingX-Rays107
2.5.2ChemicalX-RayMicroanalysis113
2.6SurfaceAnalysis:SpectroscopywithElectrons119
2.6.1InstrumentationforSurfaceAnalysiswithElectronSpectroscopy120
2.6.2AugerElectronSpectroscopy123 2.6.3X-RayPhotoelectronSpectroscopy128
2.6.4SurfaceCompositionalAnalysiswithAESandXPS134
2.6.5ComparisonofAESandXPS136
3.4MolecularSpectra 158
3.4.1VibrationalandRotationalModes158
3.4.2UltravioletandVisibleSpectroscopy(UV-Vis)162
3.4.3ClassicalModelofRayleighandRamanScattering166
3.4.4SelectionCriteriaforInfraredandRamanActivity169
3.5InfraredSpectroscopy 172
3.5.1InstrumentationforRamanandIRSpectroscopy173
3.5.2MichelsonInterferometerandtheFourierTransformInfrared(FTIR)Method174
3.5.3PracticeandApplicationofFTIR177
3.6RamanSpectroscopy 179
3.6.1Raman,ResonantRaman,andFluorescence179
3.6.2InstrumentationforRamanSpectroscopyandImaging181
3.6.3ApplicationofRamanSpectroscopyinChemicalandMaterialsAnalysis182
3.6.4Surface-EnhancedRamanSpectroscopy(SERS)183
3.7ProbingtheElectronicStructureofSolids185
3.8PhotoemissionandInversePhotoemissionfromSolids188
3.9AbsorptionSpectroscopies-ProbingUnoccupiedStates197
3.9.1X-RayAbsorptionSpectroscopy(XAS)197
3.9.2Near-EdgeandExtendedX-RayAbsorptionFineStructure(NEXAFSandEXAFS)200
3.10SelectApplications 206
3.10.1StructureofProteinsResolvedbyFTIR206
3.10.2AnalysisofCatalyticParticlesbyXASandXPS208 Summary
4.CrystallographyandDiffraction
4.1TheCrystallineState
4.1.1Lattices
4.1.2GeneralizedCrystalSystemsandBravaisLattices224
4.1.3LatticePoints,Lines,Directions,andPlanes227
4.1.4ZonalEquations 231
4.1.5AtomicSize,Coordination,andClosePacking233
4.1.6DescribingCrystalStructures—SomeExamples236
4.1.7SymmetryandtheInternationalTablesforCrystallography239
4.1.8TheStereographicProjection244
4.1.9ImperfectionsinCrystals247
4.2TheReciprocalLattice
4.3.1Bragg’sLaw:InterpretingDiffractioninRealSpace257
4.3.2TheEwaldConstruction:InterpretingDiffractioninReciprocalSpace259
4.3.3ComparisonofX-RayandElectronDiffraction262
4.4QuasicrystalsandtheDefinitionofaCrystallineMaterial266
5.2.1Photons:LampsandLasers278
5.2.2Electrons:ThermionicandField-EmissionSources282 5.2.3Neutrons
5.3InteractionsofProbeswithMatter,IncludingDamage292
5.3.1Photons
5.3.2Electrons
5.3.3Neutrons
5.3.4Protons
5.3.5Ions
5.4Ion-BasedCharacterizationMethods315
5.4.1RutherfordBack-ScatteringSpectroscopy(RBS)315
5.4.2Low-EnergyIonScatteringSpectroscopy(LEISS)325
5.4.3SecondaryIonMassSpectrometry(SIMS)328
5.4.4Induction-CoupledPlasmaMassSpectrometry(ICP-MS)331
5.4.5Particle-InducedX-RayEmission(PIXE)336
6.2.1ThePhaseAngle
6.2.2TheSuperpositionPrinciple348
6.2.3PhasorRepresentationandtheAdditionofWaves350
6.2.4ComplexRepresentationofaSimpleHarmonicWave350
6.2.5SuperpositionofTwoWavesoftheSameFrequency351
6.2.6AdditionofWavesonOrthogonalPlanesandPolarization353
6.3Huygens’Principle
6.4YoungDouble-SlitExperiment
6.6.1FraunhoferDiffractionfromaSingleSlit363
6.6.2FraunhoferDiffractionfromDoubleandMultipleSlits366
6.6.3ResolvingPowerofaDiffractionGrating369
6.6.4FresnelDiffraction
6.6.5FresnelHalf-PeriodZones371
6.6.6DiffractionbyaCircularApertureorDisc372
6.6.7ZonePlatesandTheirApplicationsinX-RayMicroscopy373
6.7VisuallyObservable:CharacteristicsoftheHumanEye375 6.8OpticalMicroscopy
6.8.1Resolution:RayleighandAbbeCriteria376
6.8.2GeometricOpticsandAberrations378
6.8.3TheOpticalMicroscope
6.8.4ConfocalScanningOpticalMicroscopy(CSOM)386
6.8.5Metallography
6.9.1p-ands-PolarizedLightWaves,andFresnelEquationsofReflection394
6.9.2OpticalElementsUsedinEllipsometry397
7.2InteractionofX-RayswithElectrons409
7.2.1ThomsonCoherentScattering410
7.2.2ComptonIncoherentScattering413
7.3ScatteringbyanAtom:AtomicScatteringFactor415
7.4ScatteringbyaCrystal:StructureFactor422
7.5ExamplesofStructureFactorCalculations425
7.5.1Face-CenteredCubic(FCC)Structure425
7.5.2Body-CenteredCubic(BCC)Structure427
7.5.3HexagonalClosePacked(HCP)Structure428
7.5.4CesiumChloride(CsCl)Structure429
7.6SymmetryandStructureFactor431
7.6.1CrystalswithInversionSymmetry431
7.6.2FriedelLaw 431
7.6.3SystematicAbsences 431
7.7TheInverseProblemofDeterminingStructurefromDiffractionIntensities432
7.8BroadeningofDiffractedBeamsandReciprocalLatticePoints433
7.9MethodsofX-RayDiffraction 437
7.9.1TheLaueMethodforSingleCrystals438
7.9.2DiffractometryofPowdersandSingleCrystals439
7.9.3Debye–ScherrerMethodforPowders443
7.9.4ThinFilmsandMultilayers:Diffractometry,Reflectivity,andPoleFigures445
7.9.5PracticalConsiderations:CollimatorsandMonochromators449
7.10FactorsInfluencingX-RayDiffractionIntensities451
7.10.1TemperatureFactor 451
7.10.2AbsorptionorTransmissionFactor453
7.10.3LorentzPolarizationFactor455
7.10.4Multiplicity 457
7.10.5CorrectedIntensitiesforDiffractometryandtheDebye–ScherrerCamera457
7.11ApplicationsofX-RayDiffraction459
7.11.1MeasurementofLatticeParameters460
7.11.2CrystalliteorGrainSizeandLatticeStrainMeasurements460
7.11.3PhaseIdentificationandStructureRefinement461
7.11.4ChemicalOrder–DisorderTransitions464
7.11.5Short-RangeOrder(SRO)andDiffuseScattering467
7.11.6 InSitu X-RayDiffractionatSynchrotrons468
7.11.7X-RayDiffractionMeasurementsonMars469 Summary 471
8.DiffractionofElectronsandNeutrons 481
8.1Introduction 482
8.2TheAtomicScatteringFactorforElectrons482
8.3BasicsofElectronDiffractionfromSurfaces485
8.3.1SurfaceReconstruction,SurfaceNets,andTheirNotation486
8.3.2ReciprocalLatticeNetsandEwaldSphereConstructioninTwoDimensions487
8.4SurfaceElectronDiffractionMethodsandApplications489
8.4.1Low-EnergyElectronDiffraction(LEED)490
8.4.2AdsorptionStudiesonSurfacesUsingLEED493
8.4.3ReflectionHigh-EnergyElectronDiffraction(RHEED)494
8.4.4RHEEDOscillations: InSitu MonitoringofThinFilmGrowth498
8.5TransmissionHigh-EnergyElectronDiffraction501
8.5.1Coherent,Incoherent,Elastic,andInelasticScattering504
8.5.2BasicsofElectronDiffractioninaTransmissionElectronMicroscope505
8.5.3KinematicalTheoryofElectronDiffraction506
8.5.4TheColumnApproximation,DynamicalDiffraction,andDiffractionfromImperfectCrystals509
8.6TransmissionElectronDiffractionMethods514
8.6.1SelectedAreaDiffraction:RingandSpotPatterns514
8.6.2KikuchiLines,Maps,andPatterns519
8.6.3ConvergentBeamElectronDiffraction(CBED)523
8.7ExamplesofTransmissionElectronDiffractionofMaterials527
8.7.1IndexingaSingleCrystalDiffractionPattern527
8.7.2PolycrystallineMaterialsandNanoparticleArrays527
8.7.3OrientationRelationshipsBetweenCrystalsorPhases529
8.7.4ChemicalOrderinMaterials529
8.7.5DiffractionfromLong-PeriodMultilayers531
8.7.6Twinning 532
8.8InteractionsofNeutronswithMatter535
8.8.1NuclearInteractions 535
8.8.2MagneticInteractions 537
8.8.3 InSitu KineticStudiesUsingNeutrons:HydrationofCement538 Summary 540 FurtherReading 542 References 543 Exercises 544
9.TransmissionandAnalyticalElectronMicroscopy 552
9.1Introduction 553
9.2ElementsandOperationsofaTransmissionElectronMicroscope558
9.2.1ElectronSources:Thermionic,Field,andSchottkyEmission558
9.2.2ElectromagneticLenses 560
9.2.3TheIlluminationSection565
9.2.4TheImagingSection:ObjectiveLensandAperture568
9.2.5SpecimenHandlingandManipulation570
9.2.6TheMagnificationSection571
9.2.7ImagingandDiffractionModes573
9.2.8ScanningTransmissionModeandthePrincipleofReciprocity584
9.2.9CorrectionofLensAberrations587
9.2.10ImageRecordingandDetectionofElectrons588
9.3Beam–SolidInteractions,ContrastMechanisms,andImagingMethods588
9.3.1ElasticInteractions 589
9.3.2Mass–ThicknessContrast592
9.3.3DiffractionContrast 595
9.3.4High-AngleIncoherentScattering: Z -ContrastImaging598
9.3.5High-ResolutionElectronMicroscopy(HREM):PhaseContrastImaginginPractice601
9.3.6MagneticContrast:LorentzMicroscopy609
9.3.7ElectronHolography
9.4AnalyticalElectronMicroscopy(AEM)andRelatedSpectroscopies617
9.4.1InelasticScatteringandSpectroscopy619
9.4.2ElectronEnergy-LossSpectroscopy(EELS)inaTEM623
9.4.3QuantitativeMicroanalysiswithEnergy-DispersiveX-RaySpectrometry641
9.4.4Microdiffraction 648
9.5SelectApplicationsofTEM 650
9.5.1ElectronTomography 650
9.5.2AnalysisofDefects:DislocationsandStackingFaults655
9.5.3ThinFilmsandMultilayers:AnExample658
9.5.4TEMinSemiconductorManufacturing:Metrology,ProcessDevelopment,andFailureAnalysis660
9.5.5DynamicMeasurementsinaTEM664
9.6PreparationofSpecimensforTEMObservations666
9.6.1ChemicalandElectrochemicalPolishing668
9.6.2Ion-BeamMilling 669
9.6.3UltramicrotomyandPreparationofBiologicalMaterials669
9.6.4PreparationofCross-SectionSpecimens669
9.6.5FocusedIon-Beam(FIB)Milling670
10.ScanningElectronMicroscopy
10.1Introduction 694
10.2TheScanningElectronMicroscope694
10.2.1TheInstrument 694
10.2.2TheEverhart–ThornleyElectronDetector698
10.2.3Beam–SolidInteractionsandSignals699
10.2.4TheIncidentProbeSizeandSpatialResolution701
10.2.5DepthofField 703
10.2.6NoiseandContrastinImaging706
10.2.7ElasticandInelasticScattering,andBeamBroadening707 10.3ImageContrastinaScanningElectronMicroscope709
10.3.1FactorsInfluencingSecondaryElectronEmission710
10.3.2TopographicalContrastinSecondaryElectronImaging713
10.3.3AngularDependenceofBack-ScatteredElectronsandTopographicInformation715
10.3.4ComparisonofSEMImageswithDifferentOperatingParameters718
10.4ChannelingandElectronBack-ScatteredDiffractionPatterns(EBSD)720
10.5ImagingMagneticDomains 722
10.5.1TypeIandTypeIIMagneticContrast722
10.5.2ScanningElectronMicroscopywithPolarizationAnalysis(SEMPA)723
10.6ProbingSampleCompositionandElectronicStructure726
10.6.1BasicsofX-RayMicroanalysisinanSEM726
10.6.2Cathodoluminescence731
10.7VariationsofScanningElectronMicroscopy732
10.7.1EnvironmentalScanningElectronMicroscopy(ESEM)732
10.7.2CombinedFocusedIon-Beam(FIB)andScanningElectronMicroscope734 10.8PreparingSpecimensforSEM736
11.ScanningProbeMicroscopy 745
11.1Introduction 746
11.2PhysicsofScanningTunnelingMicroscopy(STM)749
11.2.1ElasticTunnelingThroughaOne-DimensionalBarrier749
11.2.2QuantumMechanicalTunnelingModeloftheSTM750
11.3BasicOperationoftheScanningTunnelingMicroscope752
11.3.1Imaging 753
11.3.2TunnelingSpectroscopy755
11.3.3ManipulationofAdsorbedAtomsonCleanSurfaces757
11.4PhysicsofScanningForceMicroscopy759
11.4.1MechanicalCharacteristicsoftheCantilever760
11.4.2CantileverasaForceSensor763
11.4.3Tip–SpecimenForcesEncounteredinanSFM765
11.5OperationoftheScanningForceMicroscope767
11.5.1StaticContactModeforTopographicImaging769
11.5.2LateralForceMicroscopy772
11.5.3DynamicNoncontactModesofAtomicForceMicroscopy773
11.6ScanningForceMicroscopyInstrumentation776
11.7ArtifactsinScanningProbeMicroscopy777
11.7.1ProbeArtifacts 777
11.7.2InstrumentArtifacts 780 11.8SelectApplicationsofScanningForceMicroscopy780
11.8.1AtomicFingerprintinginFrequencyModulatedAtomicForceMicroscopy781
11.8.2MagneticForceMicroscopy(MFM)782
11.8.3ScanningThermalMicroscopy(SThM)785
11.8.4ApplicationsofAtomicForceMicroscopyintheLifeSciences786
11.8.5Dip-PenNanolithography(DPN)793
Table12.1SpectroscopyandChemicalMethods804 Table12.2DiffractionandScatteringMethods814 Table12.3ImagingMethods
1
1.1Microstructure, Characterization,and theMaterialsEngineering Tetrahedron2
1.2Examplesof Characterization andAnalysis7
1.3ProbesforCharacterization andAnalysis:AnOverview22
1.4Methodsof Characterization: Spectroscopy,Diffraction, andImaging34
1.5FeaturesofMaterialsUsed forCharacterization57 Summary59 FurtherReading59 References61 Exercises63
1.1Microstructure,Characterization,and theMaterialsEngineeringTetrahedron
Materialsscienceandengineering(MSE)isanenablingandmultidisciplinary field,impactingnearlyeveryaspectofsocietytoday.ThereachofMSE isenormous—advancedsemiconductorshavestretchedthelimitofhighperformancecomputers;opticalfibershavedramaticallyincreasedthebandwidth andspeedofintercontinentaldatatransmission;magneticmaterialsindatastorage haverevolutionizedinformationaccess,includingtheproliferationoftheInternet; light-weightmetals,polymers,andcompositeshavetransformedaircraftdesign andfuelefficiency;novelbatteriesandfuel-cellmaterialspowerthingsfromcell phonestopublicbuses;andincreasingly,innovationinmaterialsisattheheart ofbiomedicine.AsthelateWilliamBaker,pastpresidentofBellLaboratories, putitsoelegantly:“everythingismadeofsomethingandalwayswillbe!”In otherwords,MSEexemplifiestheuse-inspiredfundamentalstudiesof“Pasteur’s Quadrant”(Stokes,1997).Thedramaticsocietalimpactoftheworkofmaterials scientistsandengineerscanbeillustratedbynumerousexamples;afewofthem, includedinFigure1.1.1,areadaptedfromaspecialreportbyadistinguished panelofmembersoftheU.S.NationalAcademyofEngineering[1].
Whenweengineeranymaterial,wetailoritspropertiesforaspecificapplication.Thisrequiresthatitperforminapredictableandreliablemannerwhenit isfabricatedinthedesirableshapeor form.Thelattermaybeabulkmaterial,a composite,acoating,athinfilmorheterostructure,awireorrod,ananoparticle oritsdispersioninamatrix,asurface,ananoscalestructure,alithographically patternedelementorarray,etc.Inotherwords,wemakematerialswithsizes rangingfromtheatomictothemacroscopic,anddimensionalityrangingfrom zerotothree.Sometimes,thecriticalfeatureofinterestinthematerialmaybe deepinside;anexampleistheburiedinterfaceinmanymodernsemiconductor, magnetic,orphotonicdevicesthataredesignedandfabricatedintheformofthin filmheterostructures.
Characterizationandanalysisofmaterialsiscentraltothepracticeofmaterials sciencesandengineering.Thepropertiesofallmaterialsaredeterminedbytheir structure,bywhichwebroadlymeanthecomposition,electronicstructure,thermodynamicstate/phase,andthearrangementsoftheirinternalcomponents.The structureofmaterialscanbedescribedatvarious lengthscales orlevelsofdetail. Atthe atomic level,itdescribesthebondingandorganizationofatomsor moleculesrelativetooneanother.Atthe mesoscopic level,itreferstoan intermediate-lengthscale,betweentheatomicandmicroscopic,wherematerial propertiesaredifferentfromthebulk,oftendeterminedbyquantummechanics, anddominatedbysurfaceeffects.Thisisalsothelengthscaleofparticular interestinnanoscienceandnanotechnology(OwensandPoole,2008).At
Figure1.1.1 Thesocietalimpactofmaterialsscienceandengineeringisillustratedbyafewrepresentativeexamples. (a)Strength-to-densityratioofstructuralmaterialshasincreasedfiftyfold,comparedtocastironusedtwocenturiesago, withapplicationrangingfromlight-weighteyeglassestocompositeairplanes.(b)Thedesignofhigh-efficiencyengines withreducedenvironmentalimpactrequiresmaterialsthatarestrongathightemperature—superalloysandspecialty ceramicscanoperateattemperatureashighas1,100–1,400◦ C,withtheoreticalefficienciesof ∼80%.(c)Thestrengthof apermanentmagnet,givenbyitsenergyproduct,determinesthedesignofsmallerandmorepowerfulmotors—a100foldincreasefromthe1930sisevident.(d)Progressinthecriticaltemperatureofsuperconductingmaterials.(e)Optical fibersarenow100timesmoretransparentthantheywereinthe1960s.(f)Newhardabrasivematerialshaveincreased cuttingtoolspeedsbyafactorof100fromtheearlytwentiethcentury,makingmanufacturingprocessescheaperand moreefficient.
Adaptedfrom[1].
the microscopic—thatwhichcanbeobservedbysometypeofmicroscope— level,itreferstothearrangementsoflargergroupsofatoms,suchasgrains andthermodynamicphases,includingtheirmorphology,chemistry,and crystallographicrelationships.Asmaterialsscientists/engineers,whenweuse
Properties
Figure1.1.2 Thematerialsengineeringtetrahedron,wherecharacterizationplaysacentralrole.
theterm microstructure,wegenerallymean all relevantstructuraldetailsdescribed here,fromtheatomicuptothemicroscopic-lengthscale.Lastly,atthe macroscopic level,werefertostructurethatcanbeviewedwiththenakedeye.
Thecoreactivitiesofamaterialsscientist/engineercanberepresentedbya tetrahedron(Fig.1.1.2).Naturally,webeginwiththe synthesis ofanymaterialand then process ittoachievethedesired structure,whichinturn,determinesits properties anditsrequired performance inaneconomicalandsociallyacceptablemanner. Notethat characterization,or evaluatingthemicrostructureattheappropriatelength scale,playsacriticalroleintailoringthesynthesisandprocessingofmaterialsto achievethedesiredpropertiesandperformanceofanyengineeringcomponent. So,weconvenientlyplacecharacterizationinthecenterofthistetrahedron.Note thatcharacterization,asdiscussedinthisbook,doesnotincludemeasurementsof properties—mechanical,magnetic,electrical,thermal,etc.—thatcanbefoundin otherspecializedtextbooks.
Arangeofcharacterizationmethodsisrequiredtoelucidatethe processing–structure–property–performance tetrahedronexhibitedbythewidevarietyofmaterialsthataretailor-madeforspecificfunctionalitytoday.Thelistislongand includesmetals/alloys,ceramics,polymers,amorphousmaterialsandglassesthat donotexpressanylong-rangecrystallographicorder,semiconductors,biological orbiomimeticmaterials,composites,andnaturalmaterialslikewoodandpaper. Alternatively,wecanalsoclassifymaterialsintermsoftheirapplication,i.e. wherestructural,mechanical,functional(electrical,magnetic,optical),nuclear, biocompatibilityproperties,eitherindividuallyorinsomecombination,become important.Itmaywellbeasoftmaterialthatissusceptibletodamagewhen probed.Irrespectiveoftheclassofmaterialthatmaybeofinterest,understanding theroleofmicrostructureandtailoringittooptimizeitspropertiesiscentral toMSE.Themicrostructureofinterestmaybeacombinationofchemical, electronic,structural,crystallographic,ormagnetic(domains)features,andhas tobeelucidatedattheappropriatelengthscalethatdescribesthebehaviorofthe material.Thecharacterizationmethodsaremanyandtheonetobeappliedfor aspecificproblemhastobechosenjudiciouslyamongthosereadilyavailable. Table1.1.1providesalistof probe-based characterizationmethodsdiscussedin thisbook,especiallythosecommonlyidentifiedbyacronyms.
1 https://www.astm.org/studentmember/ metallurgybycommittee.html
Broadly,themethodsofcharacterizationusingdifferent probes areclassified as diffraction, spectroscopy,and imaging.Thephysicalprinciplesunderlying thesemethodsarethefoundationsofthisbook.Varioustechniquesfollow fromtheseprinciplesandarepresented,withvaryingdetail,asappropriatefor thiscomprehensivepresentation;naturally,detaileddiscussionsofindividual techniquesaboundinmoreadvancedtexts,includingencyclopediasof materialscharacterization(seeFurtherReading).Forworkingengineers,the AmericanSocietyofTestingandMaterials,nowknownasASTMInternational, providesdetailedstandards1 foravarietyofmaterialscharacterization
Microstructure,Characterization,andtheMaterialsEngineeringTetrahedron 5
Table1.1.1 Probe-basedcharacterizationmethods,includingacronymswhereappropriate,discussed inthisbook,withsectionsindicated.Manyofthesetechniquesarementionedinthischapter.
TechniqueAcronym/AbbreviationSection
Analyticalelectron microscopy
Augerelectron spectroscopy
AEM§9.4
AES§2.6.2
AtomicforcemicroscopyAFM§11.8
Atomprobefieldion microscopy
Back-scatteredelectron imaging
Biologicalforce spectroscopy
AP-FIM§1.4.3
§10.3.3
BFS§11.8.4.5
CathodoluminescenceCL§10.6.2
Confocalscanning opticalmicroscopy
Convergentbeam electrondiffraction
CSOM§6.8.4
CBED§8.6.3
Dip-pennanolithographyDPN§11.8.5
EnergydispersiveX-ray spectrometry
Electronback-scattered diffraction
Electronenergy-loss spectroscopy
EDXS§2.5.1.1
EBSD§10.4
EELS§9.4.2
Electronholography§9.3.7
Electronprobe microanalysis
EPMA§2.5.2.2
Electrontomography§9.5.1 Ellipsometry§6.9
Energyfilteredimaging inaTEM
Environmentalscanning electronmicroscopy
ExtendedX-ray absorptionfine structure
EFTEM§9.4.2.6
ESEM§10.7.1
EXAFS§3.9.2
FieldionmicroscopyFIM§1.4.3
FocusedionbeammillingFIB§9.6.5 Fouriertransform infraredspectroscopy
High-angleannulardark fieldimaging
FTIR§3.5.2
HAADF§9.3.4
