Tuning of the Electronic and Optical Properties of Monolayer GaSe Via Strain

This paper investigates strain effects on the electronic and optical properties of monolayer GaSe using first-principles calculations. The geometric deformation significantly alters energy dispersion, band gap, and the band edge states of GaSe. The band gap evolution exhibits both linearly and nonlinearly with the strains and is strongly dependent on the types of deformation and the direction of the modifications. The external mechanical strains also significantly tailor the optical properties of GaSe, the exciton binding energy is strongly reduced when the tensile strain is applied, while the opposite way is true for compressive stress. Moreover, the inhomogeneous strain also induces a nonuniform electronic screening environment and strong polarization in the absorption spectra. The calculations demonstrate that the electronic and optical properties of GaSe monolayer can be significantly tuned by using strain engineering which appears as a promising way to design novel optoelectronic devices.