环境压力对Si纳米结构的影响课件

JosephJ.Thomson;1897年发现电子，1906年诺贝尔奖志同道合的合作伙伴照明系统成像系统电子光学信息传递系统物镜系统信号处理系统K.Luetal,Science,304(2004)422纳米技术引起的照明技术革命（LED）Thewidthofthequantumwellis1.5nmorthreebasalplanespacing.Thehorizontalseparationcorrespondsto0.276nm,the(1-100)spacing,whichisclosetotheinteratomicseparationinGaN.ZhongLinWangetal,SCIENCE;303(2004),1348Pseudo–MackayClusters(H.Klein,1998)Al-Pd-Mn

准晶近似相中的独特位错结构

HREMimageoftheξ’-AlPdMnphaseseenalongitsbaxis.

复杂合金相所拥有的超大的晶胞常数，导致其中全位错的Burgers矢量大于10Å

。而如此大的Burgers矢量使得位错的弹性应变能变得非常大，甚至达到了在传统晶体学中不可理解的的程度。一个香蕉形拼块和一个正五边形拼块组成一维相缺陷phasonline，它的线性方向平行于b轴。

Jumpsrelatedtothedefectmotionbyonestep.?在塑性形变中，结构的转变是通过phasonlines的产生和移动来得以实现的。而phasonlines的移动是以原子相跳跃的方式，部分的破坏初始的cluster，并在新的位置重构。（2Γ-3）d=1.83ÅMetadislocation:

在phasonlines形成的周期格子中存在的一种结构缺陷。Adislocationinthelatticeofphasonlineswheresixhalfplanesofphasonlinesareinsertedontheleft-handside.Burgersvectorofmetadislocation:171Åξ’Ψ

DiffractionpatternswiththeincidentbeamparalleltothebaxisPossibilitiesmayoccur:Theycanformcloseloops;Theycanterminatewithbothendsatthesurface;Theycanterminateatadislocation.OrderedAlloysDissociateddomainboundariesinξ'-Al-Pd-Mn复杂结构合金相ξ’-AlPdMn中的畴结构缺陷(E.Ruedl)(S.Amelinckx)HREMimagesofDissociateddomainboundariesintheξ'-Al-Pd-Mnphaseviewedalongthe[010]zoneaxis,showingDBswithdifferentwidth

？PartoftheDBregionisoutlinedbywhitelines,inwhichsaw-toothedpolygonswithdifferentlengthsandacharacteristicphasonline(asindicatedwithanarrowhead)areclearlyseen.畴界这种二维面缺陷可以利用位移矢量来描述，畴界区域的结构可以通过完整晶体的两部分沿着位移矢量移动来形成。DemoofdisplacementoftwopartsinIlayer:R畴界区域缺陷的高分辨模拟SimulatedHREMimagesfortheDBplanardefectsparallelto(001)and(011)planes,respectively.caHREMimagesofDBsintheξ’-Al-Pd-Mnphaseviewedalongthe[010]zoneaxis.PartoftheDBregionisoutlinedbywhitelines,inwhichsaw-toothedpolygonswithdifferentlengthsandcharacteristicphasonlinesareclearlyseen.Fig.1.CalculatedimagesofSrTiO3,demonstratingtheimprovementinimageresolution.(A)Structureprojectedalongthe[011]crystaldirection.(B)ImageunderScherzerfocusconditionsintheuncorrectedinstrument;CS1.23mm,Z

68nm.(C)ImageforCS

40umandZ

8nm.(D)Imageforthenewimagingmode,adjustingforCS40umandZ8nm.Thecalculationsherearearriedoutforaspecimen4umthick.Theattainmentofrealatomicresolutionisdemonstratedbycalculationsfor(E)anemptyoxygencolumn,(F)a50%oxygenoccupancy,and(G)ashiftoftheoxygencolumnby0.05nm.Theeffectoncontrastislocalizedatthesingleatomiccolumn(arrow).Jiaetal.;SCIENCE299(2003),870Fig.2.ExperimentalimageofSrTiO3[011].ThesphericalaberrationcoefficientwasadjustedforCS

40um,andanoverfocusofZ

8nmwasused.Atomcolumnsinthe4-nmthickspecimenappearbrightonadarkbackground,andoxygenisatomicallyresolved.Atpositions1and2theoxygen-atomcontrastisweakerthanintheneighboringoxygen-atompositions.Thisisshownquantitativelybytheintensitytraceininset(A).ThistracewastakendirectlyfromthedigitalreadoutoftheCCDcamera.Inset(B)showsacalculatedimage,assumingareducedoxygenoccupancyof85and80%,respectively,fortheoxygen-atomcolumns3and4.Thecorrespondingintensitytrace[inset(C)]isingoodagreementwiththeexperimentaltrace(A).Fig.3.ExperimentalimagesofYBa2Cu3O7indifferentcrystalorientations.(A)A90°tiltboundary(blackarrow)separatestwocrystaldomains.Intheupperpart,thecrystalorientation(alongtheviewingdirection)isparallelto[100],whereasitisparallelto[001]inthelowerpartoftheimage.Comparisonwiththestructuremodel(C)indicatesthatallatomicpositionsofthecationsBa,Y,andCuandoftheoxygenareimagedwhiteonadarkbackgroundatatomicresolution.Intheupperpartof(A),clearlyalternatingcopperandoxygenoccupancycanbeseenalongthehorizontal[010]Cu-Ochains(redarrow).(B)Thecrystalisimagedalongthe[010]direction—i.e.,tiltedwithrespectto(A)—by90°aroundtheverticalaxis.The[010]Cu-Ochainsarenowseenend-on.ThepotentialoxygenpositionsinbetweentheCu-atompositionsintheso-calledCu-O–chainplanes(redarrow)areempty.ThisprovidesevidenceofoxygenorderingintheCu-O–chainplanes.In(A)and(B)a“124”faultalsooccurs(markedbydoublearrowheads)seenalongthe[100]and[010]crystaldirections,respectively.In(B),theenhancedbrightcontrastofthe[010]Cu-Ochains(seenend-on)inthefaultplaneindicateshighoxygenoccupancyandorderingthere.

纳米尺度结构、成分、电子结构的综合分析分辨率对t样品=10nmdADF=0.23nmdEELS=0.26nm和同步辐射分辨率相当但具有纳米尺度空间分辨的能谱技术应用：材料的尺寸和形状在纳米尺度上的涨落对电子结构的影响；界面电子结构的表征PRLv88p247002(2002)预期结果电子全息图I(X)φ(x)=F[I(x)]全息位相分布

(x)=o2V(x)/x2

V(x)=

(x)/κ电势场分布电荷类型与分布κ=e(EKE+moC2)t/hC[EKE(EKE+2moC2)]1/2t是样品的厚度。功能薄膜界面势场的电子全息研究SrTiO324o[001]倾转晶界界面1伏特2纳米掺MndFFM I FMAppl.Phys.Lett.70,3050(1997)

Appl.Phys.Lett.78,2026(2000)

Appl.Phys.Lett.78,3103(2000)

Appl.Phys.Lett.78,3496(2000)J.Appl.Phys.87,6070(2000)J.Appl.Phys.88,429(2000)

Afewmethodshavebeenusedtocharacterize

thegrowthofultra-thinoxidelayersandrevealedtheimportanceofoptimizingtheplasmaoxidationprocessandpreventing

oxidationoftheunderlyingelectrode，butnoresearchhasfocusedontheslightoxidationoftopelectrode,whichisalsoimportanttotheTMR.

主要相关国际进展TacapFMNiFe(6nm)AlOx(wedge)AFMFeMn(12nm)TabufferFMNiFe(6nm)Al层最佳氧化的隧道结截面样品的高分辨像。几对白色的平行线标注出了NiFe电极中不同晶粒中的{111}面。可以看到底电极一层一层的(111)织构匹配生长，而顶电极则是多晶取向的三维岛状生长。

EliminatethemagnetostaticcontributionInfluencecanbeneglectedhologramPhaseimageOptimum-oxidizedbarrierMTJThetopinterfaceisactuallylesssharpthanthebottominterface.Thetopelectrodeisslightlyoxidizedinoptimum-oxidizedMTJ.FilledStateat