Optical and Electrical Properties of Thin Films of CuS Nanodisks Ensembles Annealed in a Vacuum and Their Photocatalytic Activity

Effects on the optical, electrical, and photocatalytic properties of undoped CuS thin films nanodisks vacuum annealed at different temperatures were investigated. The chemical bath prepared CuS thin films were obtained at 40 degrees C on glass substrates. The grain size of 13.5 +/- 3.5 nm was computed directly from high-resolution transmission electron microscopy (HRTEM) images. The electrical properties were measured by means of both Hall effect at room temperature and dark resistivity as a function of the absolute temperature 100-330K. The activation energy values were calculated as 0.007, 0.013, and 0.013 eV for 100, 150, and 200 degrees C, respectively. The energy band gap of the films varied in the range of 1.98 up to 2.34eV. The photocatalytic activity of the CuS thin film was evaluated by employing the degradation of aqueous methylene blue solution in the presence of hydrogen peroxide. The CuS sample thin film annealed in vacuum at 150 degrees C exhibited the highest photocatalytic activity in presence of hydrogen peroxide.