First-principles Study of the Electronic and Optical Properties of SnO2 Under Strain Effects

In this work, the effect of strain on the electronic and optical characteristics of Tin oxide (SnO2) is analyzed using density functional theory (DFT). Besides, local density approximation (LDA) combined with the screened hybrid (YS-PBE0) functional are employed to analyze the material properties under strain effects. The obtained results show that the conventional SnO2 exhibits a direct band gap at the G point with a value of 3.18 eV, which agrees well with the experimental results. This is attributed to the use of combined LDA- YS-PBE0 functionals to describe the exchange correlation potential. It is also revealed from the performed first-principles calculations that the introduction of pressure leads to reduce the band gap to a specific value of 3.06 eV. On the other hand, the optical properties of strained SnO2 are analyzed by extracting the associated dielectric function. The material optical constants under strain are also extracted and compared to the conventional SnO2 structure. It is found that the introduction of pressure effects can induce significant changes regarding the material optical behavior and can promote enhanced UV absorption capabilities. This makes it appropriate for designing new Ultraviolet (UV) sensors and thin-film solar cells.