Preparation of Cu₂ZnSnS₄ thin films using spin-coating method with thermolysis and annealing

Cu₂ZnSnS₄ (CZTS) thin films are prepared using a spin-coating method with thermolysis and annealing on Mo-coated soda lime glass substrates. The thermogravimetric analysis, differential scanning calorimetry and Fourier transform infrared spectra of precursors are measured to identify the pyrolytic temperature of CZTS thin films. It is found that the decompositions of organics mainly occur before 280 °C. The phase compositions of prepared thin films are identified to be CZTS kesterites without other binary or ternary phase by X-ray diffractometer and Raman spectroscopy. It is observed through the scanning electron microscopy that there are not obvious carbon-rich layer in the interface and the CZTS thin films are composed of large densely packed grains. In addition, the structures of CZTS thin films are analyzed further by high-resolution transmission electron microscope and X-ray photoelectron spectroscopy. The resistivity and photoelectric response of CZTS thin film are also characterized, which demonstrate its potential for application in solar cells.