利用团簇的各向异性实现Te团簇薄膜的自组装  

Self-assembly of Te Clusters with Anisotropy

作　　者：沈卫锋[1] 王广厚[1] 丁锋 

机构地区：[1]南京大学固体微结构物理国家重点实验室,南京210093

出　　处：《南京大学学报（自然科学版）》2002年第2期216-222,共7页Journal of Nanjing University（Natural Science）

基　　金：国家自然科学基金 (2 9890 2 10;10 0 2 30 0 1);江苏省自然科学基金

摘　　要：在实验观察到的Te团簇薄膜有序生长模式的基础上 ,用Monte Carlo方法模拟了具有各向异性的团簇在衬底上的生长行为 .发现由于团簇的各向异性 ,将导致团簇在局部范围内的平行取向排列 ,形成畴结构 .畴的大小L(t)与退火速率和衬底温度有关 ,并得到该体系下的一个熔点Tm.这一研究表明 。Self-assembly of nanoparticles with controlled size and dimension has been extensively studied with a broad-based theoretical and experimental effort. Bowden studied the self-assembly of mesoscale objects into ordered two-dimensional arrays, and suggested that self-assembly resulted from minimization of the interfacial free energy of nanoparticles interface. In this letter, we report a novel experimental finding of domain-like self-assembled Tellurium clusters with anisotropy. The Te nanofilm is prepared by inert gas condensation method. The nanofilm's structures are identified by transmission electron microscopy, and are characterized by domain structures with local order and different orientations for different domains. Tellurium is an important semiconductor. Te has particular properties of anisotropy and nonlinear optical response, and its anisotropy is the strongest in all of the known elements. The structure of Te crystal is very exceptional; it is a helix belonging to Group P321, and this will bring on some special growth properties of its nanofilm. Based on the experiment of Te cluster film with a local order structure and Te's special microstructures, Monte-Carlo simulations have been performed for the growth properties of anisotropic clusters on the substrate. To simplify, we assume the Te cluster to be a square with two different intact faces. These Te squares are distributed randomly to a 2 D square lattice with size N×N, which satisfy periodic boundary conditions. There are three kinds of interaction energy ε AA ε BB ε CC for three different interactions, and we set ε AA∶ε BB∶ε CC=5∶3∶1. The anisotropic attractions among nanocrystals are readily apparent from these expressions, ranging from a maximum ε AA to minimum ε CC neighbours? To illustrate how anisotropy leads to the domain-like self-assemble, we perform a two-dimensional simulated annealing calculation with the anisotropic interaction of clusters showed above, where the total energy of the system-a

关 键 词：Te团簇薄膜 各向异性 畴结构 自组装 半导体材料 平行取向排列 生长行为 

分 类 号：O484.1[理学—固体物理]