Aerosol-Assisted Chemical Vapor Deposition of Transparent Conductive Gallium−Indium−Oxide Films

Aerosol assisted chemical vapor deposition (AACVD) reactions of GaMe 3, InMe 3, and 6 equiv of the donor functionalized alcohol, HOCH 2 CH 2 OMe, in toluene resulted in the deposition of colorless, transparent gallium−indium−oxide films at a range of temperatures (350−450 °C). The gallium−indium−oxide films were analyzed by a range of techniques including scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), glancing-angle X-ray powder diffraction (XRD), and wavelength dispersive analysis of X-rays (WDX). The optimum growth temperature was found to be 450 °C, which produced transparent films with a composition of Ga 0.6 In 1.4 O 3 as determined by WDX. XPS confirmed the presence of indium, gallium, and oxygen in the films. Annealing these films at 1000 °C resulted in crystalline films, and glancing-angle powder XRD showed a gallium-substituted cubic In 2 O 3 lattice was adopted with a lattice parameter, a = 9.84 Å. AFM showed that the annealed films on quartz had a root-mean-square roughness of 94−200 nm, and the work function was measured to be 4.6 eV. The four point probe method was used to determine a sheet resistivity, R s = 83.3 Ω/square, and a low electrical resistivity value (for example 6.66 × 10 −4 Ω cm in 80 nm sample thickness, as determined by side-on SEM for films deposited on glass).