Aluminum-doped zinc oxide thin films: A dual approach using experimental techniques and DFT-based calculations

Abstract

Aluminum-doped zinc oxide thin films were synthesized using ultrasonic nebulized spray pyrolysis. The influ­ence of aluminum doping (0.5 and 1 at.%) on ZnO structural, optical, and electrical properties was analyzed. X-ray diffraction revealed a contraction in lattice parameters with increasing Al content, accompanied by a change in preferential orientation from (002) to (102). Morphological analysis indicated reduced grain size and film thickness with Al doping, leading to increased electrical conductivity. Optical characterization showed that the transmittance remained above 70 % in the visible range, with a negligible variation in the band gap (~3.28 eV). Theoretical calculations based on the DFT + U approach supported the experimental observations, indicating that Al incorporation does not introduce excess charge in the ZnO host lattice. These results provide insights into the structural and electronic modifications induced by Al doping, which are relevant for developing transparent conductive oxide materials.