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

• We fabricate the CZTS absorber layer by using a single step electrodeposition.
• We analyzed general reaction mechanism for the formation of CZTS film.
• We have investigated the dependence of sulfurization of the films.
• Increasing annealing temperature, the films become better crystallinity.
• The band gaps of the annealed samples are found to be in the range from 1.9 to 1.5 eV.

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.