Annealing effect on physical characterisation and sensing properties of nanostructered AgO thin films

Abstract

Thermal evaporation (TE)was employed to create thin coatings of AgO on glass substrates. The post-annealing temperatures for the deposited films were (100, 150, and 200), respectively. The XRD data demonstrate that when annealing temperature climbed from 100°C to 200°C, the intensity of (100) plane strengthened. Regardless of the temperatures used for post-annealing, the XRD spectra show that the films are polycrystalline and have a cubic structure. The average grain size was 15.39 nm, 16.30 nm, and 17.68 nm for the intended films. When the annealed temperature rises, the dislocation density and strain value decrease. The root mean square (RMS) roughness measured via AFM images decreased from 7.33 nm to 3.64 nm. Due to annealing at 200°C, the average particle size behaved similarly and reduced from 76.9 nm to 46.5 nm. The surface roughness exhibited the same behavior and dropped from 8.77 nm to 4.46 nm at 200 o C. The sample annealed at 200°C had the highest absorbance values, whereas the sample annealed at 100°C had the highest transmittance values. As the film annealing increased, the absorption coefficient rose somewhat. The bandgap of AgO thin films falls from 1.59 eV to 1.44 eV with the rise of annealing. In contrast, the transmittance, refractive index, and Extinction coefficient also lower as the temperature rises. Sensitivity measurements indicated a reduction in sensitivity as the annealing temperature and gas concentration increased.