Crystallization and optical properties of finite sized β-Ga2O3in sol–gel derived Ga2O3:SiO2nanocomposites

Gallium oxide nanoparticles embedded in silica matrix with different molar ratios were synthesized by the sol–gel method. Powdered nanocomposite samples were annealed at 400, 500 and 900 °C. The gallium oxide nanoparticles (2–5 nm) crystallized in the β-phase at a very low temperature (∼400 °C) as against the expected temperature (>700 °C), indicating a depression of crystallization temperature under the present condition. This may be a signature of the behaviour of confined nanosized particles. The indications of only Ga–O bonds and Si–O–Si bonds in FTIR spectra and peaks of gallium, oxygen and silicon in energy dispersive x-ray analysis (EDAX) confirmed the non-existence of any impurity. Room temperature photoluminescence study of the samples shows a strong blue emission at ∼460 nm.