Comparative Analysis of Al-Doped ZnO and Ga-Doped ZnO Thin Films

We have investigated the influences of aluminum and gallium dopants (0∼2.0 mol.%) on zinc oxide (ZnO) thin films regarding crystallization, electrical and optical properties for applications in transparent conducting oxide (TCO) devices. Al- and Ga-doped ZnO thin films were deposited on glass substrates. A lowest sheet resistance of 3.3 × 103 Ω/□ was obtained for the GZO thin film doped with 1.5 mol.% of Ga after post-annealing at 650 °C for 60 min in air. All the films showed more than 85% transparency in the visible region. We have studied the structural and microstructure properties as a function of Al and Ga concentration through X-ray diffraction (XRD) and scanning electron microscope (SEM) analysis. In addition, the optical bad gap (E g) and photoluminescence (PL) were estimated.