摘 要：近年来，以石墨烯、磷烯、六角氮化硼、过渡金属硫化物为代表的二维单层材料 受到了广泛关注和深入研究。以这些单层材料为基础，进行相互堆叠，形成的异质结会表 现出一些不同于单层材料的新奇特性，具有重要的应用价值。本论文以密度泛函理论为基 础， 通过数值计算，研究了两类基于石墨烯的双层异质结---石墨烯/磷烯和石墨烯/二硫 化钼的结构和电子特性。结果表明，由于双层异质结层间的范德瓦尔斯弱相互作用，使得 双层异质结表现出一些不同于相应组份的单层材料所具有的现象和性质；石墨烯与半导体 单层材料之间可以形成肖特基接触，其接触性质可以通过改变层间距进行调控。这些结果 将为二维材料的异质结应用于纳机电系统和光电器件等领域开辟新的思路和途径。71456

毕业论文关键词：二维单层材料，双层异质结，密度泛函理论

Abstract ： Research on graphene and other two-dimensional (2D) materials, such as phosphorene, hexagonal boron nitride (h-BN) and transition metal dichalcogenides, has recently received considerable interest owing to their outstanding properties and wide applications. Reassembling the isolated atomic plane of 2D materials into designer heterostructures made layer by layer in a precisely chosen sequence has also emerged to widely study theoretically and experimentally to explore some new properties and potential applications beyond their single

components. Here, by first-principles density functional theory calculations we investigate the structural and electronic properties of 2D heterojunctions, including graphene/Phosphorene and graphene/MoS2 heterobilayers. We find that the weak interlayer van der Waals interactions in these 2D heterojunctions can induce new properties and phenomena, such as bandgap opening, charge transfer and Schottky contact, which are expected to be with great applications in efficient electronic, electrochemical and photovoltaic devices.

Keyword: two-dimensional materials，heterobilayers，density-functional theory

目 录

1 引言 4

1.1 二维单层材料概述 4

1.1.1 石墨烯 8

1.1.2 六角氮化硼 5

1.1.3 过渡金属硫化物 6

1.1.4 磷烯 7

1.1.5 其它单层材料 7

1.2 二维单层材料异质结 8

1.3 基于石墨烯的双层异质结 8

1.4 本论文主要工作 9

2 理论基础及计算程序 9

2.1 多粒子体系模型 9

2.2 量子力学从头算方法 9

2.3 密度泛函理论 10

2.3.1 Hohenberg-Kohn 定理 10

2.3.2 Kohn-Sham 方程 10

2.3.3 局域密度近似(LDA) 11

2.3.4 广义梯度近似(GGA) 11

2.4 VASP 软件包简介及其主要功能 12

3 结构建模与计算方法 13

3.1 结构建模 13

3.2 计算方法 14

4 结果与讨论