Effect of the spraying temperatures and the sulfurization on the properties of the absorber Cu2FeSnS4 thin films in a solar cell

The quaternary Cu2FeSnS4 (CFTS) is regarded like the one of the semiconductors promoting as an effective photovoltaic absorber because of their earth-abundant and non-toxic elements. The thin films were elaborated by spray pyrolysis method deposited onto glass substrates at 370 degrees C for one hour with post-sulfurization treatment at 450 degrees C for 30 min. XRD spectra analysis showed that the CFTS thin films have tetragonal structure with a main peak corresponding to the direction (1 1 2). The Raman spectrum confirmed these results with an appearance of two main peaks corresponding to the CFTS situated at the positions 289 cm(-1) and 318 cm(-1). The CFTS films exhibit a homogeneous, rough and dense topography with a thickness of about 0.8 mu m. The films of CFTS present a high absorption coefficient (>= 10(5) cm(-1)) and the direct band gap energy is found to be 1.55 eV, which confirms their use as an absorber for solar cells. (C) 2017 Elsevier B.V. All rights reserved.