Studying of cadmium oxide/ Aluminium films for optoelectronics: structural, optical and electrical characteristics

Abstract

In the results of this research, thin films of CdO-Al were produced using the spray pyrolysis (SP) technique. The primary aim was to explore how varying concentrations of aluminum (Al) influence the physical properties of the films. The X-ray diffraction (XRD) analysis confirmed the presence of a cubic crystal structure in the pure CdO films. Additionally, it revealed that the introduction of increased Al doping led to lattice shrinkage and a reduction in lattice parameters. Elevated levels of aluminum (Al) content were correlated with a decrease in crystallite size and an augmentation in lattice strain, as indicated by both scanning electron microscopy (SEM) and X-ray diffraction (XRD) data. Additionally, an X-ray photoelectron spectroscopy (XPS) examination revealed the presence of Al3+ ions within the films. The optical energy gap of CdO-Al films exhibited a slight increase, reaching up to 3% aluminum doping. The analysis of the refractive index dispersion and non-linear refractive index revealed a decreasing trend up to 3% aluminum content, with subsequent fluctuations at higher concentrations. The measurements of sheet resistance demonstrated a noticeable decrease with an increase in aluminum content, specifically up to 3%.