II/VI族半导体纳米线异质结构的生长机理、载流子分布与输运特性的研究

It is very important for both the fabracation of low dimensional nano-structure materials and the application of micro-nano optoelectronic devices to investigate controlled growth mechanism of II/VI semiconductor nanowires and the transport property of the heterostructure carrier. In this project, the first principle method combined with thermodynamic equations have been performed on ZnSe/Si and CdS/ZnS nanowires, and their axial heterostructure nanowires, and their Core/shell heterostructure nanowires etc, to study microscopic process of growth and electronic structure properties, and to find the mechanism of nucleation and self-catalytic effect of metal atoms, the temperature and growth atmosphere adsorption during the initial growth of nanowire.The origin of quantum confinement localization of carriers in the nanowires/tube has been revealed to find the distribution of carriers in nanowires by means of the electronic and structural properties calculation. Finally, the heterostructure nanowire devices are constructed. The relations between the geometry structure and size distribution of controlled growth of nanowires and high mobility performance of the quantum devices are revealed by means of the analysis of the effect of dopant concentration and its distribution on mobility and electrical conductivity of the carrier in device. The experimental results of both material structure characteristics and transport properties of carrier well be confirmed. The parameters of micro-nano quantum line device and new structures of device well be obtained. Thus, the theoretical basis can be provided for understanding new mechanism of both carrier transport and controllable growth of II/VI semiconductor nanowires.

II/VI族半导体纳米线的可控生长机理及其异质结的载流子传输性质的研究，对于低维纳米结构材料的制备和微纳米光电子器件的应用都有着特别重要的指导意义。本课题利用第一性原理方法结合热力学方程的理论计算方法，研究ZnSe/Si、CdS/ZnS等材料的纳米线，并轴异质结纳米线，及其核壳异质结纳米线生长的微观机理和电子结构性质，弄清纳米线生长初期金属原子的成核与自催化效应、温度和生长气氛吸附的微观机理；结合电子结构性质计算，揭示载流子在纳米线/管中的量子受限局域化起源，弄清纳米线中载流子的分布；最后构造异质结纳米线的器件结构，分析掺杂浓度和分布对器件载流子迁移率和电导率的影响，揭示可控生长纳米线材料的几何结构和尺寸分布与获得量子器件的高迁移率性能的关联，验证实验结果，获得微纳米量子线器件的参数和新型器件的结构方案，为理解II/VI族半导体纳米线的可控生长和载流子传输的新机理提供理论依据。

II/VI族半导体纳米线的可控生长机理及其异质结的载流子传输性质的研究，对于低维纳米结构材料的制备和微纳米光电子器件的应用都有着特别重要的指导意义。本课题利用第一性原理方法结合热力学方程的理论计算方法研究了ZnSe/Si、CdS/ZnS等材料的纳米线，并轴异质结纳米线，及其核壳异质结纳米线生长的微观机理和电子结构性质，揭示载流子在纳米线/管中的量子受限局域化起源，弄清纳米线中载流子的分布；探讨具体的生长环境中 CdS 纳米线的表面吸附物对其电子性质的影响，以及杂质在每一晶格位引起的纳米线的电子性质的变化。最后研究了二维材料黑磷场效应晶体管的双极性电学特性，讨论了单层黑磷器件的太赫兹辐射吸收的特性。为理解II/VI族半导体纳米线的可控生长和载流子传输特性的新机理提供理论依据。