In contrast to bulk semiconductors, the bandgap of two-dimensional (2D) transition-metal dichalcogenide monolayers is strongly dependent on the dielectric environment. The optical properties of these 2D materials can also be significantly modified by substrate screening. We report herein the structural, electronic, and optical properties of n-BN/WS₂ heterostructures consisting of a WS₂ monolayer on top of n layers of BN substrates (n = 1 to 4) based on first-principles calculations and theoretical analysis. The results reveal that the bandgap of the n-BN/WS₂ heterostructures decreases with increasing number of dielectric layers in the environment, while the band edge is enhanced. The 1-BN/WS₂ heterostructure with one layer of BN is apt for photocatalytic water splitting applications. The imaginary part of the dielectric function also shows that the n-BN/WS₂ layers exhibit semiconductor properties. As the number of layers is increased, the static dielectric constant increases. The n-BN/WS₂ layers also exhibit optical anisotropy. These results suggest a pathway to engineer the bandgap of 2D materials via substrate choice.

Graphic abstract

Systematic study of various properties of n-BN/WS₂ heterostructures and their potential applications.

中文翻译：

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n-BN/WS2 (n = 1 to 4) 异质结构的电子结构、光学性质和潜在应用

与体半导体相比，二维 (2D) 过渡金属二硫属化物单层的带隙强烈依赖于介电环境。这些 2D 材料的光学特性也可以通过基板筛选来显着改变。我们在此报告了基于第一性原理计算和理论分析的n -BN/WS ₂异质结构的结构、电子和光学特性，该异质结构由n层 BN 衬底（n = 1 至 4）顶部的WS ₂单层组成。结果表明，n -BN/WS ₂的带隙异质结构随着环境中介电层数量的增加而减少，而能带边缘增强。具有一层BN的1-BN/WS ₂异质结构适用于光催化水分解应用。介电函数的虚部还表明n -BN/WS ₂层表现出半导体特性。随着层数的增加，静态介电常数增加。所述Ñ -BN / WS ₂层也表现出光学各向异性。这些结果表明了一种通过基板选择来设计二维材料带隙的途径。

图形摘要

n -BN/WS ₂异质结构的各种性质及其潜在应用的系统研究。