The miniaturization of electronic devices is a continuing trend both for industrial manufacture and academic research. The study of the novel properties that emerge as the size of objects are reduced down to the nanoscale is leading to the realization of applications in optics, electronics, catalysis, chemical sensing, and many other areas. As one of the primary building blocks for future nanotechnologies, single-crystalline 1-D semiconductor nanowires have received much attention.

InN, GaN and AlN semiconductors form a continuous alloy system with direct band gaps ranging from ∼ 0.7 eV to 6.2 eV, and exhibit high mechanical and thermal stability. Collectively called III-nitrides, they have been intensely studied in recent years because of potential applications such as high efficiency solid-state lighting and photovoltaics, high power and temperature electronics, and optoelectronics. The majority of literature is focused on the development of III-nitride thin-films, however, in recent years considerable interest in nanowires and quantum dots has emerged. This dissertation focuses specifically on III-nitride semiconductor nanowires.

In the first chapter, a brief overview of nanotechnology is covered, with an emphasis on semiconductor nanowire properties and growth methods. The fundamentals of III-nitride semiconductors, some of their applications, and the advantages of the nanowire morphology are also discussed. In the second chapter, the development and application of MOCVD to the growth of GaN nanowires is introduced. MOCVD was chosen in order to facilitate the integration of nanowire technology with existing thin-film technology. The growth of high-density, high-quality wires was achieved. The physical, optical and electronic properties of the nanowires are examined. In chapter three, refinement of the growth technique to produce patterned arrays of vertically aligned nanowires is presented. Through lattice-matched substrate selection, the ability to control the growth direction of the nanowires along distinct crystallographic axes is demonstrated. The optical properties are examined and shown to vary depending on growth direction. Finally in chapter four, the development of a specialized HCVD synthetic approach is presented. Using a combinatorial approach, nanowires with complete compositional tunability are grown. These nanowires show exceptional physical and optical properties.