Rapid growth of Sb2S3 thin films by chemical bath deposition with ethylenediamine tetraacetic acid additive

Abstract

Sb2S3 is a suitable photovoltaic material because of its favorable optoelectronic properties as well as being comprised of earth-abundant and nontoxic precursor elements. The chemical bath deposition method has been widely used to deposit Sb2S3 thin films. However, longer deposition times as well as multiple depositions have been reported to prepare thicker Sb2S3 films. In order to produce good quality Sb2S3 films with a thickness greater than 1 μm within a short deposition time, we have added a small amount of ethylenediamine tetraacetic acid (EDTA) to the conventional chemical proportions used for the deposition of Sb2S3 films. The effect of EDTA, Na2S2O3, bath temperature, and the deposition time were studied. By optimizing these conditions, uniform good quality Sb2S3 thin films with a thickness greater than 1 μm could be obtained in a short deposition time of 3 h. The films prepared at the optimized conditions were annealed to improve the crystallinity. The films exhibited orthorhombic crystal structure with lattice parameters a = 1.142 nm, b = 0.381 nm, and c = 1.124 nm, and a direct optical band gap of 1.66 eV. This approach is beneficial for obtaining good quality Sb2S3 films which is ideal for solar cell applications.