Synthesis of one-dimensional Ga_2O_3 nanostructures via high-energy ball milling and annealing of GaN

摘要

β-Gallium oxide (β-Ga_2O_3) is a promising material for sensors that can withstand high-temperature, high-pressure, and corrosive environment in advanced fossil fuel power plants. Synthesis of one-dimensional nanostructures of β-Ga_2O_3, which are of particular interest, by ball milling of gallium nitride followed by annealing in nitrogen flow is attractive due to relatively inexpensive equipment and simple procedures, but the long milling time is an obstacle for widespread use of this method. In the present work, high-energy mechanical milling of GaN in a planetary ball mill is used for shortening the milling time in the fabrication of one-dimensional Ga_2O_3 nanostructures. Effects of milling parameters on the morphology of GaN powders as well as on the morphology and chemical composition of the obtained Ga_2O_3 structures are studied. When annealing was conducted in ultra-high purity (O_2 < 1 ppb) nitrogen flow, a variety of Ga_2O_3 one-dimensional nanostructures such as rods, belts, sheets, and leaf-like shapes were obtained.