Structural, morphological, compositional, and optical properties of single step electrodeposited Cu2ZnSnS4 (CZTS) thin films for solar cell application

We fabricate a Cu2ZnSnS4 (CZTS) absorber layer, by using single step electrodeposition of CZTS precursor, deposited at −1.05 V, followed by high temperature annealing in a sulfur atmosphere. X-ray diffraction pattern indicates that the as-grown sample is amorphous in nature, and polycrystalline CZTS thin films with kesterite crystal structure have been obtained by sulfurization from 450 to 580 °C. Surface morphologies of the as-grown sample show some voids with agglomerated particles. After sulfurization, the morphologies of the annealed samples become more uniform, and dense. EDAX study reveals that the sulfurized samples are nearly stoichiometric, being Cu-rich and S-deficient in composition. The band gaps of the annealed samples are found to be in the range from 1.9 to 1.5 eV.