The influence of deposition temperature on the structural, morphological and optical properties of micro-size structures of beta-Ga2O3

Abstract

Microstructures (MSs) of gallium oxide were synthetized via vapor-solid mechanism using the hydrogen-assisted chemical vapor deposition (HACVD) technique, without the aid of a carrier gas which is part of the usual CVD synthesis recipe. Deposition temperature was varied to investigate its influence on the structural, morphological and optical properties of the material. The gaseous precursor was transferred to the downstream of the reaction chamber mainly by temperature and gaseous species concentration gradients. The β-Ga2O3 MSs were assessed by XRD, FESEM, EDX and UV–vis spectrophotometry respectively. The elimination of carrier gas in the synthesis recipe proved inconsequential, and rather yielded a unique preferred crystal growth of the (1¯11) orientation. Increasing deposition temperature of the grown material led to increasing growth rate and crystallinity. Crystallite size was observed to increase from 37.69 to 158.88 nm, while the bandgap decreased from 5.01 to 4.84 eV. The optimized breakdown field was estimated to be above 9.2 MV/cm; and the activation energy of Ga2O3 in HACVD was found to be 2.86 eV/atom.