Investigation of excitonic states effects on optoelectronic properties of Sb2Se3 crystal for broadband photo-detector by highly accurate first-principles approach

The rapid demand of photodetector is increasing day by day due to its versatility of applications that affect our lives. However, it is still very challenging to produce low-cost high-performance broadband photo-detector that can detect light from near infrared to the ultraviolet frequency range for medical diagnosis and visible light communication applications. Regarding this, low-cost antimony selenide (Sb₂Se₃), with direct energy gap and strong light absorption over a wider range from near infrared to ultraviolet frequency, is considered a promising candidate material for such kind of applications. Therefore, to expose its hidden potential, detailed analysis of its structural, electronic and optical properties is very essential. To accomplish this purpose, different schemes of the first-principles calculations are used in this study. Structural properties of Sb₂Se₃ are calculated by first-principles methods realized within density functional theory (DFT) framework. Whereas, to compute the quasiparticle (QP) band structure, excitonic and optical properties, many-body perturbation theory (MBPT) based on one-shot GW (G₀W₀) and Bethe-Salpeter equation (G₀W₀-BSE) approaches are used. Our DFT calculations show that Wu-Cohen GGA (WC-GGA) reproduces lattice parameters of Sb₂Se₃ material consistent with the experimental measurements. Similarly, G₀W₀ calculations confirm the Sb₂Se₃ a direct bandgap energy material of 1.32 eV and show good agreement with the experimental results. Similarly, the results on the optical properties of Sb₂Se₃ with the inclusion of electron-hole interaction show that the exciton energy of the material is 1.28eV while its corresponding plasma energy is 10.86 eV. These values show that the investigated material can absorb photons from near infrared to ultraviolet wavelengths. It is, therefore, anticipated that this material will be useful for new-generation optoelectronic applications from near infrared to ultraviolet wavelengths.