One-step diffusion membrane assisted CBD synthesis and characterization of Cu₂SnS₃ thin films

This paper present a novel method for growing thin films of Cu₂SnS₃ (CTS) using a solution-based chemical route consisting of simultaneous precipitation of Cu_2-xS and SnS₂ performed by diffusion membranes assisted CBD technique. Diffusion membranes are used to optimize the kinetic growth through a moderate control of the releasing metal into the solution. The conditions in terms of concentration of metal species, sulfide anion and temperature required for the precipitation of the Cu₂SnS₃ compound were determined through a study of chemical equilibrium of the system SnCl₂, Na₃C₆H₅O₇·2H₂O, CuCl₂ and Na₂S₂O₃·5H₂O. These conditions were obtained solving the equilibrium equations with the help of the Visual MINTEQ 3.0 package, supported on the program MINTEQA2. X-ray diffraction (XRD) and Raman spectroscopy were used to characterize the structural properties of the CTS films. Optical, morphological and electrical properties were also studied by spectral transmittance, atomic force microscopy (AFM) and resistivity vs temperature measurements. XRD and Raman measurements confirmed the formation of the Cu₂SnS₃ phase