Annealing induced surface restructuring in hydrothermally synthesized gallium oxide nano-cuboids

Gallium Oxide (Ga2O3) nanostructures are synthesized using a hydrothermal approach and the effect of different gallium precursors on the morphology of gallium nanostructures is studied. The rice-like nanostructures are obtained in gallium chloride and gallium nitrate precursors, whereas nano-cuboids are formed in the case of gallium acetylacetonate. The size of the edge defined nano-cuboid is in the range of 0.6 μm × 0.3 μm × 0.2 μm. The as-synthesized nano-cuboids are in the metastable phase "α" and converts to a stable "β" phase after annealed at a higher temperature (~850 °C). Post synthesis thermal annealing also results in the creation of nanopores on the surface of these nano-cuboids. Pores size increases with an increase in annealing temperature till 950 °C, further increase in annealing temperature reduces the size of pores and a smoother surface appeared. The annealing induced surface restructuring offers significant alteration on nano-cuboid properties that could be beneficial for surface-related applications.