缺陷主导的GaN和AlN纳米线发光微观机理研究

项目名称： 缺陷主导的GaN和AlN纳米线发光微观机理研究

项目编号： No.11474012

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 史俊杰

作者单位： 北京大学

项目金额： 80万元

中文摘要： GaN和AlN纳米线在发光、太阳能电池、探测和场发射等方面有广泛的应用前景，引起高度重视。本项目将瞄准GaN和AlN纳米线可能存在的各种缺陷，致力于解决实验提出的三个亟待解决且有较大争议的缺陷主导纳米线发光问题：(1)GaN纳米线3.45eV发光峰、(2)极性六角GaN纳米线黄发光带(中心在560 nm)和(3)AlN纳米线2-4eV宽的非对称蓝发光带的微观起因。考虑到纳米线大的比表面、量子尺寸效应、表面原子排列和键组态的无规性及纳米线与环境的介电失配效应，基于第一性原理计算，研究缺陷对GaN和AlN纳米线电子结构和光学性质的调控和影响，澄清缺陷的本质，阐明缺陷主导的特定PL光谱的微观物理起因，探索改进相应的纳米线基发光和光伏器件性能的新途径，以丰富人们对小尺度纳米体系奇妙物理现象的认识，不仅对低维纳米结构的基础研究，而且对基于这些结构的高效纳米器件的应用都意义重大，且具有极大的挑战性。

中文关键词： 纳米发光材料；光致发光；发光机理；晶体缺陷；第一性原理计算

英文摘要： Both GaN and AlN nanowires (NWs) have very promising device application in solid state lighting, solar sells, photodetectors and field emission. We will aim at all of possible defects included in GaN and AlN NWs and solve three key issues related to their light emission dominated by defects. (1) What is the physical origin of the PL peak at 3.45 eV in GaN NWs? (2) How to understand the microscopic mechanism of the broad yellow luminescence band centered at 560 nm in polar GaN NWs? (3) What is the real physical reason of the asymmetric and broad blue luminescence band in the region of 2-4 eV in AlN NWs? Considering the large surface-to-volume ratio, the quantum size effects, the random characteristics of surface atom arrangements and bond configurations together with the dielectric mismatch between the NW and its environment, we will investigate the influence of defects on the electronic structures and optical properties of GaN and AlN NWs by using first-principles calculations. Our purpose here is to clarify the nature of defects and give an atomic-level understanding for some special PL spectra observed recently in GaN and AlN NWs and pave a new way for improving the performance of GaN and AlN NW-based nano-LED and photovoltaic devices. Our results are very useful for understanding the novel physical phenomena in low-dimensional nanomaterials and fundamental investigation together with improving the characteristics of nano-devices. The current research is a real challenge due to the difficulty of the charged defects involved in NW systems.

英文关键词： Nanomaterial for light emission;Photoluminescence;Light-emitting mechanism;Crystal defect;First-principles calculation