Biaxial strain modulation of the optoelectronic properties of F-doped defective monolayer SnS2

Abstract

Abstract The first principles approach calculates the geometrical structure, stability, and optoelectronic properties of F-atom doped S vacancy defective SnS2 systems under biaxial tensile and compressive deformation. The calculations show that all systems can be formed stably, and defects and F doping cause a tiny increase in the average bond length of the systems. The formation of defects converts an indirect bandgap system into a direct one. Substitutional doping of F atoms transforms the SnS2 structure into a p-type semiconductor. The doped system's valence band mainly originates from S-3p orbitals, Sn-5p orbitals, and F-2p orbitals. The conduction bands mainly originate from the S-3p, Sn-5s, and F-2p orbitals. The absorption and reflection peaks of the doped system with applied strain are blueshifted at the maximum peak. The biaxial compressive strain increases the band gap and decreases the doped system's refractive index and extinction coefficient. The biaxial tensile strain increases the band gap of the doped system, the hybridization of the valence band of the system is enhanced, the conductivity of the real part of the complex dielectric function of the system is increased, and the refractive index of the system is elevated. The biaxial stretching strain can better change the sensitivity of the F-doped system to visible light.