Optical and structural investigations on Sb2S2O new kermesite alloy for optoelectronic applications

Sb2S2O thin films have been prepared on glass substrates by using appropriate heat treatment of Sb evaporated thin films. X-ray analysis shows that Sb thin film annealed under sulfur atmosphere at 300 °C is mainly formed by Sb2S3. A heat treatment of the latest binary compound in air at 350 °C during six hours leads to Sb2S2O ternary material having triclinic structure with a preferred orientation of the crystallites along (1¯02) direction. Some of structural, optical and morphological characteristics have been studied. The analysis in 300-1800 nm domain of the refractive index data through Wemple-DiDomenico model leads to the single oscillator energy (E0 = 8.2 eV), the dispersion energy (Ed = 23.14 eV) and both M−1 and M−3 moments. Real and imaginary parts of dielectric constant have been also used to calculate plasma frequency, relaxation time and ε∞ permittivity. The optical conductivity exhibits a threshold of absorption of about 3.07 eV which matches the gap energy value of Sb2S2O material. Moreover, the correlation between optical conductivity and Urbach energy of Sb2S2O thin films are discussed.