（InAs）1/（GaSb）1超品格纳线第一原理研究

摘要

As the active areas and the connection part,semiconductor nanowires have ideal shapes which are beneficial to restricting the electron motion and atomic periodicity to one one-dimensional structure.The effective selection of material components in nanowires can enhance the advantages of low-dimensional structures by analyzing the features of bulk materials.Furthermore,the nanowire properties can also be tailored by controlling the internal or intrinsic characteristics such as diameters,crystallographic growth direction, structural phase,surface crystallographic plane or saturation degree,and by applying external influences such as electric,magnetic, thermal and force fields.The bulk InAs and GaSb have approximate lattice constants,thereby resulting in small lattice mismatch for InAs/GaSb heterostructures that can finally be grown into excellent infrared optoelectronic materials.Moreover,the bulk InAs has the lowest electron effective mass in binaryⅢ-Ⅴcompound semiconductors,leading to high transport features for electrons distributing most in InAs layers of InAs/GaSb superlattices.In the present work,the zinc-blend（InAs）1/（GaSb）1 superlattice nanowires（subscript denotes the number of molecular or double-atomic layers） with[001]and[111]crystallographic wire-axes have been studied by firstprinciples calculations for their structural,electronic and mechanical properties together with the rule of different nanowire diameters （from～0.5 to～2.0 nm）.We also analyze the stress effects from external forces and examine the electronic band-edge changes with strain in wire-axis direction to determine the deformation potentials.%半导体纳米线作为纳米器件的作用区和连接部分具有理想的形状,把电子运动和原子周期性限制在一维结构当中.通过体材料的已知特性,有效地选择材料组分使纳米线的低维结构优点更加突出.此外,还可以通过其他方式来调整纳米线特性,如控制纳米线直径、晶体学生长方向、结构相、表面晶体学晶面和饱和度等内部或固有的特性;施加电场、磁场、热场和力场等外部影响.体材料InAs和GaSb的晶格常数非常相近,因此InAs/GaSb异质结构晶格失配很小,可生长成为优良的红外光电子材料.另外,体材料InAs在二元Ⅲ—Ⅴ化合物半导体中具有最低的有效质量,这使得电子限制在InAs层的InAs/GaSb超晶格具有良好的输运特性.本文通过第一原理计算研究轴线沿[001]和[111]闪锌矿晶体学方向的（InAs）1/（GaSb）1超晶格纳米线（下标表示分子或双原子单层的数量）的结构、电子和力学特性,以及它们随纳米线直径（线径约为0.5—2.0 nm）的变化规律.另外,分析了外部施加的应力对电子特性的影响,考察了不同线径（InAs）1/（GaSb）1超晶格纳米线的电子带边能级随轴向应变的变化,从而确定超晶格电子能带的带边变形势.