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.