Influence of deposition conditions on structural, electrical, and optical properties of cadmium oxide thin films deposited using the spray pyrolysis technique

Abstract

In this study, thin films of cadmium oxide (CdO) were deposited on soda-lime glass substrates using the simple spray pyrolysis technique using a cadmium acetate precursor. The results regarding the structural, electrical, and optical properties of the layers as a function of the substrate temperature ranging from 280 to 340 °C, spray rate ranging from 5 to 20 ml/min, and volume of solution ranging from 50 to 125 ml were systematically studied. The X-ray diffraction (XRD) analysis revealed that all the thin films had a polycrystalline nature with the fcc structure of single-phase CdO. The analysis also showed peaks related to (111), (200), (220), and (311) planes. The field emission scanning electron microscopy (FE-SEM) images showed that the morphology surface of the thin films was spherical. The atomic force microscopy (AFM) analysis demonstrated that the roughness of thin films ranged from 21.16 to 60.9 nm. The Hall effect and thermoelectric studies revealed that the films exhibited an n-type conductivity. The Hall effect measurement study also showed that the carrier concentration (n) and carrier mobility were of the order of 1019 cm− 3 and 10− 2 cm− 2/v s, respectively. The obtained values for the optical bandgap ranged from 2.29 to 2.56 eV, where the amount of the optical bandgap for the thin films decreased as the substrate temperature increased.