Gallium Oxide Thin Films from the Atmospheric Pressure Chemical Vapor Deposition Reaction of Gallium Trichloride and Methanol

The reaction of gallium trichloride and methanol under atmospheric pressure chemical vapor deposition conditions leads to the production of gallium oxide thin films on a variety of substrates. Scanning electron microscopy (SEM) indicated that an island growth mechanism predominated. X-ray photoelectron spectroscopy (XPS) revealed binding energy shifts of 530.6 eV for O 1s and 20.3 eV for Ga 3d. The films were X-ray amorphous. Energy-dispersive X-ray analysis (EDXA) and electron probe microanalysis (EPMA) gave coherent elemental compositions, indicating that a single phase Ga 2 O 3 was made, with negligible impurity levels. The films showed little optical reflectance (∼10%) and 65−75% total transmission from 400 to 800 nm. Gas-sensing experiments indicated that the films responded best to a reducing gas at 450 °C.