Structural, optoelectrical analysis, and optical properties of indium-doped Al2O3 thin films synthesized by spray pyrolysis

In this study, thin films of aluminium oxide (Al2O3) and indium-doped Al2O3 with doping ratios of 0%, 5%, 7.5%, and 10% were prepared by spray pyrolysis technique at 350 ?. The phase compositions of the Al2O3 and indium-doped Al2O3 films were determined using x-ray diffraction analysis. The structural parameters of the studied films, such as the strain function (epsilon), crystallite size (delta), and dislocation density (a) were evaluated. The transmittance and reflectance spectra of the prepared films were analysed to evaluate the optical and optoelectrical parameters, including the optical free-carrier concentration (N-opt), optical conductivity (sigma(opt)), absorption coefficient (alpha), optical dielectric constants (epsilon(1) and epsilon(2)), and ener(g)y gap (E-g). The optical results indicate that the investigated films exhibited direct optical transitions. The nonlinear optical constants of the sprayed films were determined using the Miller equations. The hot-probe technique was used to determine the majority of carriers in the investigated films. Electrons were the majority carriers in the indium-doped Al2O3 films. The high optical transparency and the tendency of being an n-type semiconductor make indium-doped Al2O3 thin films suitable for producing a novel window layer for thin-film solar cells.

Automated summary

In this study, indium-doped aluminum oxide thin films were prepared using the spray pyrolysis technique, and their phase composition, structural parameters, and optical properties were analyzed. The results showed that the indium-doped aluminum oxide films exhibited high optical transparency and were n-type semiconductors, making them suitable for use as window layers in thin-film solar cells.