Determination of the optimal conditions for the deposition of Cu2ZnSnS4 (CZTS) thin films by spray pyrolysis using Taguchi method

Thin films of Copper zinc tin sulfide (Cu₂ZnSnS₄, CZTS) is one of the promising semiconductor materials used in over recent years as a next generation of absorber materials in thin film solar cells thanks to its tunable direct band gap energy, large absorption coefficient, cost effective and eco-friendly nature. The aim of this present study is to investigate the influence of parameters deposition of CZTS thin films using the L₂₇ orthogonal array of the Taguchi´s design of experiments. CZTS thin films were deposited on ordinary glass substrate by spray pyrolysis technique. The Taguchi design was used to evaluate the effects of seven deposition parameters called factors namely the ratios [Cu]/([Zn]+[Sn]), [Zn]/[Sn] and [S]/[Metal], solution rate, air-compression, time of deposition, substrate temperatures on optical properties of as-sprayed films. The identification of the most influent factors of the deposition process on the band gap energy of as-sprayed films is also done. Under the optimized configuration, the CZTS films showed optimal gap energy of 1.56 eV. The Taguchi analysis employed in the present investigation led to optimize process parameters for the most optimal deposition conditions.