First principles study of BAs/MoSi2N4 van der Waals heterostructure: tunable electronic and optical properties via vertical strain

Constructing van der Waals heterostructures from layered materials can form new optoelectronic devices with superior performance to the individual monolayers. Here, we use first-principles calculations to explore the modulation of a two-dimensional BAs/MoSi2N4 van der Waals heterostructure via strain, including the structure stabilities, electronic properties, charge transfer, and optical properties. Our calculated results reveal that the BAs/MoSi2N4 heterostructure has a direct bandgap of 0.72 eV and type-I band alignment. In addition, the BAs/MoSi2N4 heterostructure exhibits enhanced light absorption in the visible light region. The electronic properties of the BAs/MoSi2N4 heterostructure are tunable by vertical strain, exhibiting a direct to indirect bandgap transition as well as a type-I to type-II band alignment transition when the vertical distance is reduced. Our research provides a comprehensive understanding of the electronic and optical properties of the BAs/MoSi2N4 heterostructure and could be helpful for their potential applications in optoelectronic devices.