Characterization of CdS films and CdS/Si heterojunctions prepared by ultrasonic spray pyrolysis and their response to light

In this work CdS thin films were deposited onto glass and p-Si substrates by ultrasonically spraying of precursor solutions prepared in molarity ranging from 0.025 M, to 0.1 M. Structural investigations revealed that all films have hexagonal structure and mean crystallite size was found to be in the range of 18 nm–21 nm. On the other hand, CdS films exhibited 65–70% optical transmittance and band gap energy for all films was found to be about 2.42 eV. Electrical measurements of CdS/Si heterojunctions were carried out under both dark and illumination conditions. Calculated ideality factor and zero-bias barrier height ranged from 3.02 to 2.66 and 0.74 eV–0.78 eV according to TE theory whereas they ranged from 6.91 to 4.73 and 0.71 eV–0.74 eV according to Cheungs’ method. Increase in reverse saturation current when heterojunctions were illuminated indicated that they have good sensitivity to solar light. © 2020 Elsevier B.V.Türkiye Bilimsel ve Teknolojik Araştirma Kurumu, TÜBITAK: 111T057This work was supported by The Scientific and Technological Research Council of Turkey (TÜBİTAK) under the project number 111T057

Study of Ultrasonically Sprayed ZnO Films: Thermal Annealing Effect

ZnO thin films were deposited on microscope glass substrates by ultrasonic spray pyrolysis technique. The effects of annealing under various temperatures on the optical and structural properties of ZnO thin films were analyzed. The as-deposited and annealed ZnO thin films were investigated by UV/VIS spectrophotometer and X-ray diffractometer. Some of the optical properties of the films such as transmittance, absorbance and band gap energy were investigated by UV/VIS spectrophotometer. The crystallinity levels of the films were investigated, the structural parameters such as diffraction angle, full-width at half maximum, lattice parameters, grain size and dislocation density were calculated and structural properties were analyzed. X-ray diffraction patterns indicated that the ZnO films had a polycrystalline hexagonal wurtzite structure