Ab initio calculations of antimony sulphide nanowire
Abstract We have performed first-principles calculations on orthorhombic antimony sulphide (Sb2S3) nanowire using full-potential linearized augmented plane wave (FP-LAPW) method based on the density-functional theory (DFT) as implemented in WIEN2k package to investigate the electronic and optical properties. Engel–Vosko generalized gradient approximation (EV-GGA) is used as exchange-correlation functional. The nanowire is simulated in the [001] direction with vacuum in two directions using supercell method. The results are compared with Sb2S3 bulk results obtained in our pervious study. We have found that the electronic and optical properties significantly change in Sb2S3 nanowire. The density of state (DOS) for Sb2S3 nanowire calculated is higher than bulk Sb2S3 and from the electronic band structure, the indirect band gap is about 0.12 eV where this value is much lower than Sb2S3 bulk. However, this value is much lower than experimental value. The optical properties including absorption coefficient, reflectivity, refractive index and energy loss function are derived from the calculated complex dielectric for photon energy up to 20 eV to understand the optical behavior of Sb2S3 in one-dimensional (1-D) nanostructure. From analysis, the optical response of Sb2S3 nanowire demonstrate quite interesting optical behavior for one-dimension (1-D) nanostructure. The absorption coefficient for Sb2S3 nanowire is considerably higher in visible light range than Sb2S3 bulk.