凝聚态物理报告课件.ppt

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,Anisotropy in stability and,Youngs modulus of,hydrogenated,P+tr,silIcon nanowires,Anisotropy in stability and,1,owe team,owe team,2,Statement,This article is available online on 31,December 2007,Because the article published earlier,Nano technology in recent years with new,development,may appear new theory or,experiment we did not study about it so this,discussion is limited to this article,Statement,3,content,Background,The research content,The significance of this research,content,4,Background,Recent experiments have shown that small,silicon nanowires siNWs)with various sizes and,crystallographic orientations can be successfully,synthesized.it was possible to fabricate single,crystalline si nanowires with diameters as small,as1 nm and lengths of a few tens of,micrometers,SUPERCOURSE CHINA,Background,5,Background,How to get the materials,With the oxide-assisted growth methods,the synthesized nanowires usually consist of a,crystalline core surrounded by an outer oxide,layer.Further removal of the oxide layer by,acid treatment may lead to hydrogen-,passivated Si nanowires as thin as 1nm 4,SUPERCOURSE CHINA,Background,6,The research content,we investigate energetic relative sta bility,and mechanical properties of the hydrogen,passivated siNWs with various diameters and,growth directions using first-principles,methods To compare the physical properties,and to understand the possible reason for a,preferential growth direction,nanowires,grown along the 100,110,111 and 112,crystallographic orientations have been,studied,The research content,7,凝聚态物理报告课件,8,Nanowires with various,crystallographic,orientations,In all the sinws considered,the dangling bonds on the,surface are fully,terminated with h atoms,so that each si,atom lying on the,8含爸,nanowire surface is,tetrahedrally coord,nated,舍争,lIlI,Nanowires with various,9,Research methods,Perform Geometry optimizations using DFT,implemented in the dMol package,Chose All-electron treatment and double numerica,basis including p-polarization function(DNP),The exchange-correlation interaction was treated,within the generalized gradient approximation,(GGA)with the functional parameterized,Research methods,10,凝聚态物理报告课件,11,凝聚态物理报告课件,12,凝聚态物理报告课件,13,凝聚态物理报告课件,14,凝聚态物理报告课件,15,凝聚态物理报告课件,16,凝聚态物理报告课件,17,凝聚态物理报告课件,18,凝聚态物理报告课件,19,凝聚态物理报告课件,20,凝聚态物理报告课件,21,凝聚态物理报告课件,22,凝聚态物理报告课件,23,凝聚态物理报告课件,24,凝聚态物理报告课件,25,凝聚态物理报告课件,26,。