Preparation and characterization of Cu2ZnSnS4 thin films by two-stage process

Cu2ZnSnS4 (CZTS) a quaternary semiconductor is potential candidate for absorber layer in thin-film heterojunction solar cell. Achieving CZTS thin films is really a challenging task using chemical methods. In this work, an attempt is made by mixing binary and ternary compound semiconducting films for the growth of CZTS films. Initially, ZnS thin films have been deposited by spray pyrolysis technique onto soda-lime glass substrates held at a substrate temperature of 698 K. Later, copper tin sulfide (Cu2SnS3 [CTS]), a ternary compound semiconducting film, has been deposited using spray pyrolysis technique onto ZnS-coated substrates held at a substrate temperature 598 K. For achieving CZTS films, ZnS/CTS films were annealed in sulfur ambiance at different annealing temperatures in a two-zone tubular quartz furnace. The structural, optical, electrical, and surface morphological studies are carried out for these thin films.