Issue 26, 2023

Tunable electronic and optical properties of a type-II AlAs/GaS heterojunction: first-principles calculations

Abstract

In this paper, the geometric structures and electron-optical properties of AlAs/GaS heterojunctions and Se-doped AlAs/GaS heterojunctions are calculated based on first-principles of density functional theory (DFT). At the same time, the influence of the AlAs layer's 5° rotation stacking method on the AlAs/GaS heterojunction is discussed. The results show that the AlAs/GaS heterojunction is a type-II van der Waals heterojunction (vdWH) with a direct bandgap of 0.974 eV, and the Z-scheme electron transfer mechanism is more conducive to the separation of photogenerated electrons and holes. Both semiconductor-to-metal transitions can be achieved by applying an external electric field and strain. Under the action of an external electric field and uniaxial strain, AlAs/GaS maintains the type-II energy band alignment throughout the process. When biaxial strain is applied, the heterojunction is accompanied by a direct–indirect bandgap transition. It is worth mentioning that the optical absorption of the AlAs/GaS heterojunction is significantly higher than that of the two monolayers, and the absorption range is wider. The above characteristics indicate that the AlAs/GaS heterojunction has wider applications in fields such as photodetectors.

Graphical abstract: Tunable electronic and optical properties of a type-II AlAs/GaS heterojunction: first-principles calculations

Supplementary files

Article information

Article type
Paper
Submitted
15 mar 2023
Accepted
08 maj 2023
First published
09 maj 2023

CrystEngComm, 2023,25, 3812-3825

Tunable electronic and optical properties of a type-II AlAs/GaS heterojunction: first-principles calculations

J. Wang, J. Xuan, X. Wei, Y. Zhang, J. Fan, L. Ni, Y. Yang, J. Liu, Y. Tian, X. Wang, C. Yuan and L. Duan, CrystEngComm, 2023, 25, 3812 DOI: 10.1039/D3CE00255A

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