Synthesis, optical characterization and DFT calculations of electronic structure of Sb2O3 films obtained by thermal oxidation of Sb2S3

•Sb2O3 thin films have been synthesized by oxidizing of Sb2S3ones in air at 400 °C.•Transmission T (λ) and reflection R (λ) coefficients are measured in 300–1800 nm.•Band gap and Urbach energies are achieved using opticalT (λ) and R (λ) coefficients.•Density Functional Theory (DFT) calculation is used for this oxide.•Energy band structures, density of states and dielectric function are reached by DFT.

Sb2O3 thin films have been synthesized on glass substrates by oxidation of Sb2S3 thin films for 6 h in air atmosphere at 400 °C. Surface topography was performed by atomic force microscopy. Optical response has been investigated in the wavelength range between 0.3 and 1.8 μm. In the transparent region, the refractive index follows Cauchy's law, while, in the absorption zone, Wemple-DiDomenico model is verified. It leads to the single oscillator energy (E0 = 7.2 eV) and the dispersion energy (Ed = 33.1 eV). Plasma frequency, relaxation time and ε∞ permittivity have been estimated using the real and imaginary parts of dielectric constant. The dissipation factor exhibits an absorption edge of about 3.83 eV which matches the gap energy value of Sb2O3 material. The electronic properties of Sb2O3 such as the energy band structures, density of states were carried out using density functional theory (DFT). We have employed the semi-local gradient corrected exchange correlation functional (GGA-PBE). The calculated total and partial density of states indicate that the top of valance band is mainly built upon O-2p states and the bottom of the conduction band mostly originates from Sb-5p states. Moreover, the optical properties including the dielectric function, refractive index and extinction coefficient are investigated and analyzed. The calculated results are discussed and compared with our experimental results.