Abstract
The room-temperature (RT) growth of ultraviolet-emitting hexagonal gallium nitride (h-GaN) on a sapphire substrate using photochemical vapor deposition (PCVD) has been demonstrated. A high photoluminescence (PL) peak at 3.47 eV was observed at 5 K, indicating a high-quality crystalline structure for h-GaN. A RT PL energy peak of 3.40 eV indicated the reduction of thermal residual stresses in GaN. In addition, the RT growth resulted in the formation of dendrite-like GaN, which originated from the low kinetic energy of the precursors for migration. A high PL peak at 3.55 eV observed at 5 K in the dendrite-like GaN indicated the quantum size effect.