第Ⅲ主族金属硫属化物二维异质结能带调控及光学性质研究

Heterostructures in 2-dimensional (2D) materials have attracted intensive research interests from both condensed matter physics and material science fields. The formation of heterointerface is an effective approach to enhance photo-generated electron-hole separation and reduce their recombination, which is useful to improve the electronic and optical properties of 2D composite materials. In this project, the effects of vertical van der Waals heterostructure and in-plane lateral heterostructure on the electronic and optical properties of 2D group IIIA metal chalcogenides will be studied in details by the first principles calculations. The charge transfer, band bending, and photo-excited electron-hole separation at the heterointerface will be investigated. In addition, the key factors such as carrier mobility and optical absorption coefficient will also be determined. Furthermore, we will exploit the defect and strain-engineered modulation on the electronic and optical properties of 2D group IIIA metal chalcogenides heterostructures. The outcome of this project could enrich the understandings of heterostructures in 2D materials, which provide theoretical reference for design of new 2D composite based nano-devices.

新型二维复合材料中的异质界面是当前凝聚态物理和材料物理领域的研究热点之一，寻找和发现合适的异质结构可促进光生电子-空穴对的有效分离，同时降低其复合几率，从而显著提高二维复合材料本身的电学及光学性能。本项目拟以第Ⅲ主族金属硫属化物为研究对象，通过第一性原理模拟计算的方法，系统地研究二维体系中纵向范德瓦尔斯异质结和横向共价型异质结电子结构及光学性质；揭示异质结界面处电荷转移、能带弯曲的相关机理以及其对光生电子-空穴对的作用规律；量化二维异质结体系载流子迁移率、光吸收系数等重要性能指标；探索应力、缺陷等因素对异质结体系电子结构及光学性质的调控机制。通过本项目的研究，可以加深和拓展科研人员对二维异质结体系自身性质的理解和认识，为探索基于二维复合材料的新型纳米电子器件提供理论依据。

我们按原定的研究计划推进项目的研究，项目进展比较顺利，取得了一定研究结果，三年共计发表SCI论文23篇。我们主要研究了金属硫化物单层及异质结构相关的电子和光学特性，计算了载流子迁移率、光吸收系数、光电转换效率等重要参数，分析了光生载流子的大小、传输机制、以及电子-空穴复合寿命。同时我们还考虑了掺杂、尺寸效应等因素对二维金属硫化物材料性质的影响，并探索了其在光电器件、自旋电子学等方面的应用。