Effects of cadmium doping on the physical and sensing properties of nanostructured CuO thin films

This investigation used sol-gel deposition to create undoped CuO and CuO: Cd thin films. All films of undoped CuO and CuO: Cd phase exhibit four dominating peaks at 35.52 degrees, 38.84 degrees, 53.37 degrees, and 68.23 degrees, which are correspondingly assigned to the (022), (200), (020), and (220) planes, according to X-ray diffraction analysis. The dislocation density reduced from 60.55 to 49.94, the strain decreased from 26.98 to 24.60, and the grain size of the produced films measured by XRD was 12.85-14.15 nm. Atomic force microscopy (AFM) was used to study the morphology. SEM analysis showed increased aggregation with higher Cd content, resulting in a more uniform porous structure. The optical band gap decreases for all samples as the cadmium content increases, ranging from 2.28 to 2.14 eV. Similarly, the refractive index and extinction coefficient values decrease as the cadmium content increases for all samples. The gas sensor detects H2 2 (375 ppm) using CuO film cadmium doping, which enhances sensitivity, CuO: 4% exhibits highest resistance. Sensitivity decreases with higher doping, indicating reduced sensor responsiveness.