Solar Energy, Vol.211, 613-621, 2020
Growth and optical properties of nanocrystalline Sb2Se3 thin-films for the application in solar-cells
Antimony selenide (Sb2Se3) is a promising material for thin-film solar-cells due to its attractive optoelectronic properties with the desirable band gap. In the present work, four different Sb2Se3 films were grown on Si/SiO2 (100) substrates at ambient temperature using ultra-high vacuum molecular beam evaporation technique and different evaporation temperatures. The compositional analysis with the help of wavelength-dispersive X-ray spectroscopy measurements demonstrate that there is a loss of Se in the as-deposited samples. However, the Xray diffraction study indicates that the as-deposited films are nanocrystalline in nature, with average crystallite size slightly increasing with the evaporation temperature. The blue shift of Raman peaks with the increase of evaporation temperature indicates the possibility of the presence of small amount of compressive strain in the crystal lattice and it appears because of the anion vacancy (VSe) due to the loss of Se. The obtained band gap value ranges from 1.075 eV to 1.21 eV, which indicate that the as-deposited nanocrystalline Sb2Se3 films are suitable for application in thin-film photovoltaic solar-cells. The tuning of the band-gap with the evaporation temperature opens a new road to optimize the device efficiency for the low-cost thin-film photovoltaics.