二维黑砷及其异质结的电子结构与光电器件研究

Recently, theoretical studies have predicted that the two-dimensional (2D) black-arsenic (b-As) with the same layered and puckered honeycomb structure of black phosphorus, has remarkable physical properties, such as tunable bandgap, high carrier mobility, and strong in-plane electrical and thermal anisotropy. Meanwhile, a recent experimental study shows that the b-As has good ambient stability. As a promising 2D layered semiconductor, b-As has attracted wide attention in opto/nano electronic devices. This project aims at studying the key issues on the electronic band structure and carrier transport properties of b-As. The electronic and optical properties of monolayer and few-layer 2D b-As will be explored by experiments and theoretical calculations. We will give reliable solutions to improve its ambient stability by exploring the degradation mechanism of b-As crystals. We will also design and fabricate the 2D b-As and its heterojunction based field effect transistors and photodetectors to achieve high carrier mobility (close to the theoretical value) and broad spectrum, high sensitivity detection. The aim of this project is to understand the basic physical properties of 2D b-As, design and fabricate the b-As based electronic and optoelectronic devices with high performances. This project provides important theoretical and experimental basis for the studies of b-As in multifunctional micro/nano electronic and optoelectronic applications.

最新理论预测，与黑磷同结构的二维黑砷具有带隙可调、高的载流子迁移率、强的电学及热学各向异性等优异的物理性能；同时，研究发现其具有较好的环境稳定性，是一种极具应用前景的二维层状半导体材料，引起了国内外学者的广泛关注。本项目拟系统地研究二维黑砷的电子能带结构及器件输运方面的关键科学问题，通过实验与理论相结合的方式详细研究单层及少层二维黑砷的电子结构及光学性质等基本物理性质；并探究二维黑砷晶体的退化机制，给出提高其环境稳定性的可靠方案；在此基础上，设计并制作二维黑砷及其异质结基场效应晶体管，获得与理论值接近的载流子迁移率；同时，制作二维黑砷及其异质结基光电探测器，实现宽谱、高灵敏度探测。通过本项目的实施明确二维黑砷的基本物理性质，设计并制作出具有高性能的电子及光电器件，为其在新型微纳光电学领域的应用提供重要的理论及实验依据。

与黑磷同结构的黑砷，具有带隙大、高载流子迁移率、强各向异光电热输运性质等优异的物理性能及高的环境稳定性，在高性能电子器件、光电器件等领域具有重要的应用前景，近年来得到了科学界的大量关注和研究。本项目主要研究了二维黑砷晶体的晶体取向光学判断方法及光学、电学各向异性；二维黑砷晶体的相变及稳定性；外场可逆调控的自旋-能谷耦合的Rashba效应及反常量子霍尔态；二维黑砷/WSe2异质结的制备及其超快光电器件应用。基于所研究内容，得出了如下成果：（1）从理论及实验上得出了黑砷沿不同晶体取向，其物理性质的差异性，光电器件测得的电子和空穴最大迁移率沿着面内扶手椅（AC）方向上；测得的最大电子迁移率各向异性比约为2.68，空穴迁移率各向异性比约为1.79，最大电子迁移率为451.5 cm2 V-1s-1，空穴迁移率最大值为406.6 cm2 V-1s-1；（2）发现在3.48 GPa的临界压力下，体系发生从黑砷到灰色砷的相变，并且在3.48和5.37 GPa压力范围内黑砷和灰砷两相共存，然而当压力大于5.37 GPa后黑砷完全转变为灰砷结构；（3）黑砷/WSe2异质结光电器件，开路电压为0.39V，短路电流为3.48*10^-9A，并且栅压可调；当栅压及偏压都为零时，由于内建电场的存在，光照下仍然具有很好的工作性能。