G0W0 plus BSE calculations of quasiparticle band structure and optical properties of nitrogen-doped antimony trisulfide for near infrared optoelectronic and solar cells application

Abstract

Theoretical calculations of structural, electronic, excitonic and optical properties of N-doped Sb2S3 are studied using highly accurate first-principles approach within many-body perturbation theory (MBPT) formalism. The calculated structural parameters of undoped Sb2S3 within Wu-Cohen’s generalized gradient approximation (WC-GGA) are reasonably close to those obtained in experimental measurement. Many-body perturbation theory (MBPT) based on the G0W0 approximation is used for the quasiparticle (QP) band structure. The bandgap value of 1.70 eV for the undoped Sb2S3 crystal within G0W0 approximation is consistent with the experimental value of 1.70–1.80 eV. When one atom of N is introduced into Sb2S3 at Sb site, the doping effects modified the band gap from 1.70 to 1.17 eV. Also, by introducing one atom of N to S site, the band gap value reduced to 0.96 eV. Our findings confirmed that non-metal doping narrow the energy gap of semiconductor materials. The optical properties of pure and N-doped Sb2S3 are computed using G0W0 plus Bethe-Salpeter Equation (BSE) which include both electron-electron (e-e) and electron-hole (e-h) interactions. The optical gap for Sb16S24, Sb15N1S24 and Sb16S23N1 were found to be 1.54, 0.97 and 0.82 eV, respectively. The narrowing effects and strong optical absorption of N-doped Sb2S3 suggest that the investigated material is suitable for solar cells and near infrared optoelectronic applications.