Preparation and optical properties of prism-shaped GaN nanorods

Large quantities of prism-shaped GaN nanorods were prepared by a thermal CVD reaction between Ga and NH3 on LaAlO3 crystal substrates. The distinct morphology of the GaN nanorods lies in their prism-like out shape and most of them have a quadrilateral cross section. The Raman spectrum of the GaN nanorods shows two additional bands at 255 and 419 cm(-1). Moreover, a large red shift of A(1)(LO) phonon has been observed compared with that of bulk GaN crystals. Room-temperature photoluminescence measurement reveals a broad emission ranging from 2.5 to 3.5 eV with some fine structures, which are believed to be associated with the defect levels.