Gallium nitride (GaN) nanopencils and nanotowers have been synthesized by chemical vapor deposition (CVD) method using the reaction of Ga₂O₃ and ammonia. The observed morphology of GaN nanopencils is divided into two parts: the bottom is a nanowire with large diameter; the top is a nanowire with small diameter. The observed morphology of GaN nanotowers is a layer structure. The formation mechanism of GaN nanopencils and nanotowers is a vapor-liquid-solid (VLS) mechanism. The turn on field of 2.6 V/μm is obtained for GaN nanopencils and the turn on field of 4.1 V/μm is obtained for GaN nanotowers, which are sufficient for ?eld emission ?at panel displays and cold electron sources in display devices. This growth of GaN nanopencils and nanotowers will facilitate flexible design of device architectures for nanoelectronics.