Enhancing the conductivity of Al-doped ZnMgO films via aerosol deposition method

Abstract

In this paper, we investigate the conductivity enhancement in Zn1-xMgxO2 thin films with variable aluminum (Al) concentration deposited by spray pyrolysis on silicon (Si) substrates. The morphology of the films was investigated using scanning electron microscopy (SEM), and their chemical composition was analyzed using energy-dispersive X-ray spectroscopy (EDX). The average crystallite size in Zn0.95Mg0.05O films was 105 nm, while in Zn0.85Mg0.15O films it decreased to 40 nm, according to SEM analysis. Atomic force microscopy (AFM) measurements showed a decrease in the root mean square (RMS) surface roughness from 44 nm to 12 nm as the Mg concentration increased. Xray diffraction (XRD) analysis revealed that the crystalline structure of the films remained largely unaffected at lower Mg concentrations. The electrical properties of ZnMgO:Al thin films were evaluated by measuring the current-voltage (I-V) characteristics in the dark, in a voltage range from 0.1 V to 5 V. The results indicated that films with an optimal Al concentration of 1% exhibited the highest conductivity. After a vacuum heat treatment for 1 h at 400 °C, the conductivity of films increased by a factor of 15 (at 1% Al). These results demonstrate the potential of Al-doped ZnMgO thin films as efficient transparent conductive materials, particularly when optimized with appropriate Mg and Al concentrations and post-deposition annealing.