Tunable electronic and optical properties of two-dimensional ZnSe/AlAs van der Waals heterostructure
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T.C. : SOLAR ENERGY MATERIALS AND APPLICATIONS
Tunable electronic and optical properties of two‑dimensional ZnSe/ AlAs van der Waals heterostructure Fang Yao1,2 · Xiaolong Zhou1,2 · Aihu Xiong1,2 Received: 26 February 2020 / Accepted: 26 May 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Heterostructure formed by combining a single material has outstanding electronic and optical properties, and therefore it has received great attention. In this work, we constructed a ZnSe/AlAs heterostructure. Moreover, based on first-principles calculations of density functional theory (DFT), its stacking orders, electronics, optical properties and the effects of Ge doping on the heterostructure were studied. The results show that the ABI (the Zn atoms of the ZnSe layer are above the As atoms of the AlAs layer) stacking with an interlayer spacing of 2.75 Å is thermodynamically stable. Additionally, it has a direct bandgap of 0.986 eV which is less than the bandgap of the ZnSe and AlAs monolayers. By changing the interlayer distance, the external electric field and the plane strain, the bandgap of the ZnSe/AlAs heterostructure exhibits tunability and is accompanied by a semiconductor–metal transition. Importantly, compared with the single layer, the light absorption capacity of the ZnSe/AlAs heterostructure is significantly enhanced, especially in the ultraviolet region. The addition of Ge will shrinks the bandgap of the ZnSe/AlAs heterostructure and caused a direct–indirect transition. The light absorption peak of the heterostructure was slightly red-shifted, which was helpful to improve its absorption in the visible light region. The above results indicate that the ZnSe/AlAs heterostructure is expected to be a good candidate for optoelectronic devices and nanoelectronics. Keywords ZnSe/AlAs heterostructure · First-principles calculations · Doping · Electronic properties · Optical properties
1 Introduction Since the single-layer graphene was successfully prepared in 2004 [1], two-dimensional (2D) atomic-thin layer materials have received great attention due to their novel physical phenomena and broad prospects in the field of nanoelectronics [2, 3]. A large number of two-dimensional materials such as silene, germane, and transition metal chalcogenides have been widely used [2, 4]. While single 2D materials are being studied in depth, another area of research has emerged and
* Xiaolong Zhou [email protected] 1
Department of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, China
Key Laboratory of Advanced Materials of Yunnan Province and Key Laboratory of Advanced Materials of Non‑Ferrous and Precious Rare Metals Ministry of Education, Kunming University of Science and Technology, Kunming 650093, China
2
has continued to evolve over the past few years, that is, a heterostructure made by coupling different 2D materials. The basic principle is: a single layer is stacked on another single layer, and the two rely on weak van der Waals (vdW) forces
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