外力作用下單晶納米顆粒的動態(tài)結(jié)構(gòu)表征.pdf

1、東南大學(xué)碩士學(xué)位論文外力作用下單晶納米顆粒的動態(tài)結(jié)構(gòu)表征姓名：朱逸宇申請學(xué)位級別：碩士專業(yè)：電子科學(xué)與技術(shù)；微電子學(xué)與固體電子學(xué)指導(dǎo)教師：孫立濤；賀龍兵20120530AbstractThisthesismainlyfocusesonthecharacterizationofdeformationandmasstransfermechanismsofmetalnanoparticlesencapsulatedincarbononions

2、underexternalforcesbasedoninsitutransmissionelectronmicroscopyThemaincontentscomprisethreeparts1Thedeformationprocessesofsingle—crystallineAuandPtnanoparticlesaredirectlyobservedinallinsitutransmissionelectronmicroscopeT

3、heexertedextemalforcesgeneratedbytheselfcontractionofcarbononionscouldsqueezethemetalnanoparticlesdrasticallyTheresultsindicatethatforAunanoparticleswithsizesevenleSSthan35nm嬲wellasPtnanoparticleswhosestackingfaultenergy

4、isrelativelyhigh，deformationtwinningcallbothbegenerated111eformationoftwinningstructureisattributedtotheGPapressuregeneratedfromcarbononions’Sselfshrinking2Themasstransferprocessesofmetalnanoparticlesencapsulatedincarbon

5、onionsareobservedbyin—situtransmissionelectronmicroscopyBycombiningebeamirradiationandinsituheating，themassmigrationofAuandPtnanoparticlehasbeenobservedinrealtimeItshowsthatAuorPtnanoparticlesareinitiallycompletelyencaps

6、ulatedinthecarbononionsThen，theAUPtnanoparticlesgraduallymigrateoutwardsthecarbononionshellsandeventuallypenetrateoutofthegraphitesheets111eresultsshowthatthemassmigrationprocessisrelatedtoseveralfactorssuchastemperature

7、，ebeamirradiationdose，thicknessofcarbononionshellsandsizeofthemetalcorenanoparticleThispenetrationprocessofmetalcoreoutofthecarbonshellsisfoundtobeattributedtothe”openclose”processofthecarbononionsunderebeamirradiationan

8、dthermalheatingThedefectsgeneratedbycollisionsbetweenenergeticelectronsandcarbonatomscouldprovidepathwaysformetalatomstOdiffuseoutTheobservedgeneration，migrationandannihilationofthedefectsincarbonshellsfurtherprovedourhy

9、pothesis3Thedeformationprocessesofcarbononionsareinvestigatedin鋤insitutransmissionelectronmicroscopebydirectlyexertingforcewithamanipulationprobe111eobservationsshowthatcarbononionsCanreverttoitsinitialgeometryfromdeform

10、edshapeswhentheexternalforceisunloadedItindicatesthatthecarbononionsaresomewhatductileandflexibleFurthermore，thestructureofthecarbononionbecomesmoreorderedafterrepeatedsqueezingandstretching，exhibitingmechanicalannealing