Effect of deposition temperature on the growth mechanism of chemically prepared CZTGeS thin films

The Cu 2 ZnSnGeS 4 (CZTGeS) thin films were deposited by the spray pyrolysis method at different substrate temperatures without further sulfurization. The influence of various deposition temperatures on the surface morphology, microstructure, optical properties, chemical, and phase composition were investigated. The substitution mechanism of Sn/Ge in the crystal lattice of CZTGeS depending on deposition temperatures was studied. It was shown that a variation in substrate temperature has a strong effect on the surface morphology of the films. The X‐ray diffractometer (XRD), transmission electron microscope (TEM), and Raman spectroscopy (RS) analysis showed that CZTGeS films were polycrystalline with a kesterite‐type single‐phase structure and a preferential orientation of (112). The RS‐mapping analysis showed the distribution of intensities on the surfaces of the films. Optical measurements showed that CZTGeS films are highly absorbing in the visible region, and the optical band gap is shifted from 1.89 to 1.84 eV.