Analysis and assessment of the bandgap of Al5AgX(ZnO)95-X thin films composed of nanoparticles

Abstract

Dip-coating sol-gel method was applied to deposit thin films of Al₅Ag_X(ZnO)_95-X on soda-lime glass substrates. This research helps us understand how Ag affects the physical and optical properties of the films. We used advanced techniques like HRTEM, HRSEM, and XRD to analyze the films' structure. This approach explores potential uses for these materials in various fields. These studies suggest that as-deposited thin films are composed of rod-shaped particles, and the shape was found to change from thick to fine with the increase in Ag content. The amount of dopant has a significant impact on its properties and crystallinity. We observed an increasing number of particles transitioning into smaller sizes with the rise in Ag content. Optical absorptions (300–900 nm) at room temperature suggest a direct bandgap that increases with an increase in doping content. This is an indication of the presence of defect states and the high density of localized states. The width of the Urbach tails in the localized states shows a narrowing trend with an increase in doping content. This could potentially be attributed to a decrease in the band tails, leading to an increase in the optical band gap. Moreover, as-synthesized material indicated superb chemical stability. We observed significantly higher binding energy and transparency in our as-synthesized samples. We also observed a remarkable blue shift in the absorption spectra, which shifted towards the lower wavelength side with the addition of more Ag content.