Оптические свойства ван-дер-ваальсовых гетероструктур на основе 2D-монослоев борофена, нитрида галлия и оксида цинка

Abstract

In this paper, we consider two new atomic models of van der Waals vertical heterostructures of metal-semiconductor type based on a 2D buckled triangular borophene with metallic conductivity and graphene-like 2D monolayers of gallium nitride GaN and zinc oxide ZnO, which are semiconductors. Using the density functional theory, the equilibrium configurations of supercells of the borophene/GaN and borophene/ZnO heterostructures are found and their thermodynamic stability at room temperature is shown. Within the framework of the nonstationary first-order perturbation theory, the optical characteristics (complex permittivity and absorption coefficient) are calculated in the electromagnetic radiation wavelength range of 0.2–2 μm. The presence of anisotropy in the optical properties of the borophene/GaN and borophene/ZnO heterostructures is established when the direction of light polarization is chosen. This is due to different manifestations of the optical properties of the constituent monolayers of the heterostructure. When light is polarized in the direction of the zigzag edge of the GaN/ZnO (along the X axis), the optical properties of GaN and ZnO semiconductor monolayers are predominantly manifested. When light is polarized in the direction of the zigzag edge of the borophene monolayer (along the Y axis), the optical properties of borophene manifest themselves. A synergistic effect has been found from the combination of borophene and ZnO monolayers in the composition of the borophene/ZnO vertical heterostructure, which manifests itself in the form of a section of the increasing plot of the real and imaginary parts of the complex permittivity in the infrared region for both directions of light polarization. It is shown that the difference in the values of the absorption coefficient of the borophene/GaN heterostructure between the UV and visible ranges can reach ~ 7 times, between the UV and near IR ranges - ~ 14 times, and for the borophene/ZnO heterostructure this difference can be up to ~ 6 times and up to ~18 times, respectively. It is predicted that borophene/GaN and borophene/ZnO heterostructures can be used to create UV radiation detectors.