Chemical Deposition of Rodlike GaOOH and β-Ga[sub 2]O[sub 3] Films Using Simple Aqueous Solutions

Rodlike GaOOH particles and films were successfully prepared in a large scale from a simple aqueous gallium nitrate solution. First, a hydrothermal treatment of the solution at led to the formation of GaOOH rods, and their subsequent heat-treatments at promoted transformation into having the similar particle morphology. Second, using the same aqueous solutions, strongly -axis-oriented GaOOH films consisting of rodlike particles could be deposited on substrates through chemical solution processes. It was found that heterogeneous nucleation of GaOOH was enhanced by coating thin metal oxide ( , rutile , anatase , and MgO) underlayers on quartz glass substrates, thereby resulting in the formation of uniform films. Transparent films were obtained by heat-treatments at higher temperatures. Upon excitation by ultraviolet light , the films exhibited visible green luminescence.