Feasibility study on synthesis of gallium oxide nanostructures on glass substrate by chemical vapor deposition

Abstract

Synthesis of metal oxide semiconductor films on amorphous glass substrate by using chemical vapor deposition (CVD) reactors operating at temperature ≥ 650 °C has seemingly been impossible over the years, due to glass substrate's tendency to undergo deformation at high temperatures. In the present work, Ga2O3 nanostructures (NSs) are being deposited on amorphous glass substrate by a CVD route. The films are fabricated at 950°C for durations of 60, 90, 120 and 150 min, respectively in a mixed atmosphere of N2 and H2. The effects of growth duration on the crystal structure, microstructure, stoichiometry and optical bandgap of Ga2O3 NSs are investigated in detail. X-ray diffraction data reveals polycrystalline Ga2O3α-β bi-phase. Crystallite size of the films is found to increase with prolong deposition time. Field-emission scanning electron microscopy unveils surface morphology comprising primarily of faceted aggregates as the underneath layer and a few nanostrips at the top. Energy dispersive X-ray spectroscopy reveals gradual rise in Ga/O atomic ratio with increased growth duration. The optical absorbance measurements of the films a show slight shift of the absorption edge to longer wavelengths and the bandgap decrease from 4.60 to 4.51 eV with an increase in reaction time, attributed to rising Ga/O ratio and an increase in film thickness. The results presented are expected to pave way for the fabrication of different nanomaterials on amorphous glass substrates by using high-temperature CVDs.