Effect of the annealing and the spraying time on the properties of CZTS thin films prepared by the “Spray sandwich” technique

Abstract

We have investigated synthesis conditions and some properties of sprayed Cu2ZnSnS4 (CZTS) thin films to determine the best preparation conditions for the realization of CZTS-based photovoltaic solar cells. The thin films are made by means of spraying sandwich. To optimize the preparation conditions of the CZTS films, two series of experiments are performed. In the first series, the sprayed duration was changed from 20 to 60 min. In each series, effect annealing was investigated. The X-ray diffraction shows, on one hand, that the best crystalline was obtained after annealing for 60 min as sprayed duration. On the other hand, these CZTS films exhibit the Kesterite structure with preferential orientation along the [112] direction. Raman spectrum indicated the presence of principal Stannite peak 336 cm−1. SEM showed that the surface of CZTS was uniform. After the annealing treatment, we estimated the optical band-gap energy of the CZTS thin film exhibiting the best crystalline as 1.5 eV which is quite close to the optimum value for a solar cell.