Preparation and characterization of CdS prepared by hydrothermal method

An attempt has been made to examine the Cd²⁺ source concentration effect in the structural, morphological, optical, electrical, and dark current features of CdS films. The nano films have been successfully carried out onto glass substrates by hydrothermal technique at 130 °C for 1 h. Cadmium sulfate salt was used as a source of Cd precursor with various concentrations 0.08, 0.12, 0.14, and 0.2 M. The polycrystalline nature with a mix of cubic and hexagonal system of CdS films structure with the discriminatory orientation of H(002)/C(111) was identified by X-ray diffraction studies. Further, the Field emission-scanning electron microscope (FE-SEM) analysis has revealed a unique morphology as strings-like and flower-like nanostructures. It was clearly observed the existence of CdS nanograins as building units with an average grain size of 24 nm and 15 nm of 0.08 M and 0.12 M CdS thin films, respectively. The computed optical band gap was found in the values range of 2.1–2.3 eV. The Electrical analysis revealed that variation in CdSO₄ molarity reduced the electrical resistivity from 2.1 × 10⁸ to 3 × 10⁶ (Ω.cm). Photoconductivity studies showed that the best ratio of the photocurrent to the dark current ratio I_ph/I_d was 2 × 10⁴ for CdS that was prepared with 0.12 M. The Photoconductivity properties of these films have been presented to show that such films can be useful for photodetector device applications.