Synthesis, Structural, Optical and Optoelectrical Properties of the Chemically Deposited Cu2BaGeS4 Thin Films

In this work, thin films of copper barium germanium sulfide (Cu2BaGeS4) were generated via the chemical bath deposition technique. The X-ray diffractometer identified the Cu2BaGeS4 layers' crystal structure. It showed that the Cu2BaGeS4 films have a hexagonal structure. The EDAX results demonstrated stoichiometric composition, which validated the composition of the Cu2BaGeS4 layers. However, the Cu2BaGeS4 sheets under investigation showed a direct energy gap, as demonstrated by the linear optical analysis, with the E-g falling from 1.61 to 1.42 eV as the sample thickness rose from 239 to 463 nm. As the film thickness increased, the refractive index and Urbach energy values improved as well. Additionally, the examined Cu2BaGeS4 sheets' optoelectrical indices, including optical dielectric constants, electrical conductivity, optical mobility, and optical conductivity, improved with thickness. This work shows that increasing the layer thickness enhanced the magnitudes of the nonlinear optical index of the novel Cu2BaGeS4 sheets. Cu2BaGeS4 layers tended to acquire p-type properties, as demonstrated by the hot probe test.<br />(c) 2023 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited.