Effect of Thin Film Deposition Method on Growth, Structural, and Optical Properties of ZnO:Al Films

ABSTRACT

Wide bandgap semiconductors such as ZnO:Al are widely researched for UV‐photodetector applications. Here, we report the comparative study of deposition‐method‐dependent AZO thin‐film growth and their functional properties. Structural analysis (XRD) shows that dip‐and spin‐coated films exhibit dominant (101) peak, whereas magnetron‐sputtered films show strong (002) c ‐axis orientation. Williamson–Hall analysis of XRD data indicates that sputtered AZO films have better crystallinity and a tensile microstrain state. Magnetron‐sputtered AZO films have a higher bandgap ( E _g = 3.56 eV), but lower Urbach energy ( E _U = 173.37 meV) as compared to solution‐processed thin films ( E _g = 3.40 eV, E _U = 246.7 meV). Surface roughness, FFT, and power spectral density‐based fractal analysis of AFM data further suggest that solution‐processed films exhibit high roughness, diffusion‐limited nucleation, and partial grain coalescence, whereas sputtered films display dense, smooth morphology with uniform grain distribution. I – V characteristics reveal that dip‐coated films exhibit SCLC‐like and trap‐filling‐dominated conduction. In contrast, spin‐coated and sputtered films show near‐Ohmic conduction. The combined analysis establishes a strong correlation between deposition method, microstructure, disorder, and charge transport. These findings highlight the importance of controlling growth conditions to tailor the structural and optoelectronic properties of AZO thin films.