基于二维过渡金属硫化物异相平面异质结自旋器件的设计

Recently, with much progress been made in the study of two-dimensional transition metal dichalcogenides (TMDs) electronics, its giant spin splittings makes it a potential material for the design of spintronics devices. However, the low carrier mobility and poor electrode compatibility severely limits its applications in spintronics. This project arms to construct a suitable electrode in-planemonolayer TMDs heterojunction with different phases (TMDs heterojunction) device. Based on the density functional theory, the Boltzmann transport equation and the quantum transport theory, the theoretical calculation method of carrier mobility in heterojunction has been studied and improved. By optimizing the different phases connection methods, the TMDs heterojunctions are constructed to achieve the seamless connection between the electrodes and the semiconductor and reduce the Schottky potentials Barrier. Using physical or chemical methods modulation such as doping, edge modification, stress and electric field the micro-mechanism of its electrical and magnetic characteristics is revealed. It also explores the intrinsic relations between the spin-splitting and charge transport, and puts forth thetheoretical design of TMDs based on spintronic devices with both excellent charge transport capability and spin characteristics which offers a reliable theoretical basis for the purposeful synthesis or characterization of the target. The research of this project will provide reference for good electrical contacts between electrodes and semiconductors in low dimension, and contribute to of TMDs-based electronic devices in spintronics.

基于二维过渡金属硫化物(TMDs)电子学方面的研究近年来取得了很大进展，大的自旋劈裂等使其成为自旋电子器件的潜在材料。但低载流子迁移率及较差的电极适配性，严重限制它在自旋电子学中的应用。本项目旨在构建电极适配的TMDs异相平面异质结自旋器件，从密度泛函理论、玻尔兹曼输运方程和量子输运理论出发，研究及改进载流子迁移率计算方法，寻求有效调节TMDs体系载流子迁移率的可行方法；通过优化异相连接，实现电极与半导体的无缝接触，降低肖特基势垒，并采用掺杂、表面修饰、应力和电场等物理化学调制，研究TMDs异相平面异质结的电学性质及磁性特征的微观机理；深入探索自旋劈裂与电荷输运的内在关系，提出兼具优异电荷输运能力和自旋特性的TMDs基自旋电子器件的设计方案。本项目的研究将为低维度下调控电极与半导体间接触提供理论基础，促进TMDs基自旋电子器件方面的发展。

二维范德华异质结将两种或两种以上二维层状材料按照一定顺序堆垛形成，通过对组合而成的“新”材料的性质进行人工调控，实现全新概念和功能的电子器件。研究范德华异质结的传输机制，具有深远的基础理论意义和广阔的应用背景。本项目从密度泛函理论、玻尔兹曼输运方程和量子输运理论出发，研究及改进载流子迁移率计算方法；深入探讨结构、掺杂、应力等物理化学方法对范德华异质结输运性能的影响，阐明其电学性质及磁性特征的的微观机理，提出了自旋器件的理论设计方案。.该项目经过三年的深入研究，取得了一些重要研究结果：改进和发展载流子输运理论计算方法，从电子分布的非局域化图像出发，同时考虑声学声子散射、光学声子散射以及杂质等因素的对电荷输运性能的影响，还在计算迁移率的过程中运用有效插值修正了能带计算方法。.围绕二维材料范德华异质结的输运问题展开研究，利用相变接触构建了基于2H半导体相和1T金属相MoS2的平面异质结，研究其电子性质、原子结构及其稳定性，实现金属与半导体的良好接触，研究blue Phosphorue/CsGe(Sn)Br3范德华异质结和CH3NH3PbI3/MoS2范德华异质结的电子结构、电荷迁移率以及光吸收性质等模拟计算，发现结构、掺杂、应力等手段能调控范德华异质结输运性能。利用侧向电场、电子掺杂对扶手椅型蓝磷纳米带边缘态自旋劈裂的影响，运用不对称的边缘氢化促进石墨烯纳米带自旋载流子的空间分离且实现稳定的自旋输运等理论模拟并设计了自旋特性电子器件。.通过本项目的研究，改进和发展载流子输运理论计算方法，研究了结构、掺杂、应力等对范德华异质结输运性能的影响，阐述了其电学性质和磁性特征调控的微观机理，并提出一些具有优异自旋输运性质的纳米器件设计方案。这些研究将为二维材料新型范德华异质结器件的设计及应用提供借鉴。