Strain modulation of electronic and optical properties of monolayer MoSi2N4

The strain engineering is an important approaches to modulate the electronic and optical properties of materials. Recently, a new two dimensional material monolayer MoSi2N4 has been successfully synthesized with excellent electronic performance. The electronic properties of monolayer MoSi2N4 without and with in-plane strain are systematically investigated by first-principles calculation. The calculation results reveal monolayer MoSi2N4 is an indirect bandgap semiconductor with bandgap 1.74 eV (PBE) and 2.31 eV (HSE06), but it can be transformed to a direct bandgap under the certain in-plane strain, such as 3% and 4% biaxial compressive strain. In-plane strain can effectively modulate the band structure, bandgap, and the carrier effective mass. Furthermore, the optical properties of unstrained and transformed to direct bandgap situations are calculated. The light absorption capacity of monolayer MoSi2N4 is stronger in the ultraviolet band, and can be changed when it is transformed to a direct bandgap. The electrical and optical properties can be modulated by strain engineering, making it is a promising candidate of strain-modulated optoelectronic devices.