Structural, optical and electrical properties of wet-chemical deposited β-gallium oxide nanostructured films

Abstract

Wide bandgap metal oxides offer high resistance to the charge flow, thus have interesting feature of charge storage that eventually can be considered for memory-based applications. Among different wide bandgap metal oxides, gallium oxide (Ga2O3) has suitable properties for memory devices. However, high quality Ga2O3 films are necessary for utilizing the potential of this material in memory and other electronic devices. The wet-chemical deposited Ga2O3 films mostly suffer from quality issues, therefore dedicated efforts to develop high quality Ga2O3 films using wet-chemical approach are required. Hence, this thesis work focuses on the development of effective protocols for wet-chemical deposition of Ga2O3 nanostructured films and improve the quality of the films. Primarily, the gallium oxide (Ga2O3) nanostructures are synthesized using hydrothermal technique. 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 as-synthesized nano-cuboids are in the metastable phase “α” and converts to a stable “β” phase after annealing at higher temperature (~850°C). Post synthesis, thermal annealing also results in the creation of nano pores on the surface of these nano-cuboids. Pore 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 appears. The annealing induced surface restructuring offers significant alteration on nano-cuboid properties that could be beneficial for surface-related applications.