First-principles study of shear strain on F- doped GaSe

Abstract The present study investigates the synergistic regulation mechanism of F doping and biaxial shear strain on the electronic structure and optoelectronic properties of single-layer GaSe materials based on density functional theory (DFT). The findings suggest that the application of dopants and strain exerts a substantial influence on the electronic structure and optical response of GaSe. F doping has been demonstrated to significantly alter the electronic density distribution of GaSe, enhance the static dielectric constant, and reduce the band gap. The application of shear strain, particularly in the XY direction, has been demonstrated to enhance the optical absorption and reflection properties of GaSe. This enhancement is characterized by a shift in the absorption peaks towards higher energy regions and a gradual increase in the reflection peaks. However, an examination of the data reveals a discernible trend: as shear strain in the YX direction increases, there is a concomitant suppression of optical absorption and reflection. This suppression is particularly pronounced in the high-energy region, where a significant decrease in reflectance is observed. With regard to the energy loss function, the synergistic effect of F doping and shear strain altered the material’s plasmonic excitation behavior, indicating that strain has a significant influence on the electronic collective excitation of the material. The combined influence of F doping and shear strain exerts a significant regulatory effect on the electronic and optical properties of GaSe, manifesting particularly in directional disparities in optical response under strain-controlled conditions. The findings of the present study provide a theoretical basis for strain engineering to modulate the optoelectronic properties of GaSe materials and offer design guidelines for their application in optoelectronic devices.