Optimization of the annealing temperature for formation of spin-coated copper zinc tin sulfide thin films without sulfurization step

Abstract

Determination of optimal annealing condition has important implications in fabricating optimized and efficient absorber copper zinc tin sulfide thin films. In this work, the kesterite copper zinc tin sulfide thin films were sol-gel spin-coated and were annealed at various temperatures ranging from 350 °C to 550 °C in a nitrogen atmosphere for 1 hr. The optimal annealing temperature of the pure kesterite phase is found to be 470 °C, where the films have a good morphology surface without any cracks, nearly stoichiometric, large grain size 63 nm, high optical absorption coefficient 104 cm−1 and ideal energy band gap 1.5 eV.