Structural, electrical and optical properties of Cd1−xGdxO nanocomposite thin films

Gd-doped CdO thin films with various Gd compositions were prepared on glass and Si wafer substrates using a vacuum evaporation technique. The influence of varying Gd composition on structural, electrical, and optical properties of the prepared films were systematically investigated. Experimental data indicate that Gd3+ doping slightly stress the CdO crystalline structure and change its optoelectronic properties. The bandgap of Gd-doped CdO suffers narrowing by about 40% due to a small (0.2%) doping level. The electrical behaviours of the Gd-doped CdO films show that they are degenerate semiconductors. The 0.6% Gd-doped CdO film shows increase its mobility by about eight times, conductivity by 150 times, and carrier concentration by 20 times, relative to undoped CdO film. However, the largest mobility of 66.7 cm2/V s was obtained for 0.2% Gd-doped CdO film. From transparent-conducting-oxide point of view, the Gd is effectively suitable for CdO doping. Finally, the absorption in the NIR spectral region was studied in the framework of the classical Drude theory.