A facile route to synthesize β-Ga2O3 nanoparticles from γ-polymorph through a rapid microwave route and their optical properties

Abstract

Due to the wide bandgap, monoclinic structure and thermodynamic stability, β-polymorph form of Ga2O3 nanomaterials is well-received for various applications. However, as the γ-Ga2O3 is difficult to synthesize, less attention has been paid towards it and its conversion to β-polymorph. This paper reports the single-step synthesis of γ-Ga2O3 using a microwave-assisted procedure. In this regard, γ-Ga2O3 powders are synthesized in minutes using benzyl alcohol as the solvent using gallium acetylacetone as the precursor. The XRD of the as-prepared powders indicates the formation of the γ-Ga2O3 phase, the very broad peaks indicative of the small crystallite size as confirmed by TEM. The γ-Ga2O3 powders were annealed at different temperatures and the complete phase conversion of γ-Ga2O3 phase to β-Ga2O3 phase happens at 700 °C. The TEM analysis shows the crystallite size to be ≈10 nm for the annealed β-Ga2O3 phase. The as-prepared nanopowders show very weak luminescence under excitation and in contrast, a blue-green emission is observed in case of annealed powders. This confirms the presented strategy as having the potential to use β-Ga2O3 nanopowders for different optoelectronic applications.