Time-Dependent Growth and Characterization of Copper-Alloyed Cadmium Oxide Thin Films for Optoelectronic Applications

Abstract: This study investigates the influence of deposition time on the structural and optical properties of copper- alloyed cadmium oxide (Cu:CdO) thin films synthesized via the solution growth technique. The films were deposited on pre-treated glass substrates at room temperature, with deposition times ranging from 30 to 150 minutes. Optical characterization revealed that the films exhibit high absorbance in the ultraviolet (UV) region, decreasing towards the near-infrared (NIR) range. The absorbance ranged from 11.69% to 27.91% (at 1100 nm) and 13.40% to 43.97% (at 300 nm), while transmittance varied from 36.33% to 51.37% (at 300 nm) and 77.94% to 52.59% (at 1100 nm), depending on deposition time. The bandgap energy was observed to decrease from 2.30 eV to 1.95 eV as deposition time increased. Film thickness increased from 102.35 nm to 490.80 nm due to prolonged material accumulation. Structural analysis confirmed the cubic phase of CdO with a preferential orientation along the (111) plane. Crystallite size increased from 22.05 nm to 29.89 nm, while dislocation density decreased from 2.15 × 10¹⁵ to 1.28 × 10¹⁵ lines/m², and microstrain reduced from 4.32 × 10⁻³ to 3.47 × 10⁻³, indicating improved film quality. These findings suggest that Cu:CdO thin films have potential applications in window coatings, thermoelectric devices, and solar energy conversion systems.

Keyword: Thin films, Solution growth, Cadmium oxide, Alloy, Copper, time deposition

1.0