Growth of β-$Ga_2O_3$ Nanorods and Photoluminescence Properties

β-$Ga_2O_3$ nanorods were successfully fabricated through annealing $Ga_2O_3$/Mo films deposited on the Si (111) substrate by radio frequency magnetron sputtering technique. The morphology and structure of the as-synthesized nanorods were characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and energy dispersive X-rays spectroscopy. The results show that the formed nanorods are single-crystalline $Ga_2O_3$ with monoclinic structure. The diameters of nanorods are 200 nm and lengths typically up to several micrometers. A photoluminescence spectrum at room temperature under excitation at 325 nm exhibits two strong blue-light peaks located at about 413.0 nm and 437.5 nm, attributed to the recombination of bound electron-hole exciton in β-$Ga_2O_3$ single crystal. The growth process of the β-$Ga_2O_3$ nanorods is probably dominated by conventional vapor-solid mechanism.