Growth of CZTS by co-sputtering and sulfurization for solar cell applications

Abstract

Earth abundant copper-zinc-tin-sulfide (CZTS) is an important class of material for the development of low cost and sustainable thin film solar cells. Fabrications of CZTS thin film is carried out by magnetron co-sputtering the metallic and sulfide targets and post deposition sulfurization. We sputter Cu using DC power and ZnS and SnS using RF power. In order to study its structure properties and to establish the best growth conditions, Raman spectroscopy and Glazing incident XRD analysis were carried out. These studies indicated that the grown CZTS film have a kesterite with good crystallinity and strong preferential orientation along (112) plane. SEM analysis revealed a homogeneous, compact surface morphology and large grains throughout the thickness of the film. The grown CZTS film demonstrated an optical absorption coefficient higher than ~ 6x104cm-1 and optical band gap of 1.45 eV. The sheet resistance, carrier concentration, mobility and activation energy of the CZTS film are 2.52 kΩ, 1.86 x 1018 cm-3, 1.92 cm2V-1s-1, and 37.8 meV, respectively. These optical and electrical properties are suitable for thin film solar cell fabrication.