Gallium-nitride-based materials for blue to ultraviolet optoelectronics devices

Breakthroughs in materials growth have enabled extremely high-efficiency blue and green GaN light emitting diodes (LED's) to be achieved for the first time. Blue LED's with external quantum efficiency exceeding 9% have enabled hybrid GaN/phosphor white lamp LED's. GaN LED's complete the primary color spectrum and have enabled bright and reliable fall-color solid-state displays to he realized. Recently, room-temperature operation of continuous wave current-injection blue-violet lasers emitting at 417 nm has further increased the possible applications for GaN-based optoelectronic devices. In this paper, we review the key technologies for GaN-based materials and devices. Developments in the methods for thin-film deposition by metalorganic chemical vapor deposition and molecular beam epitaxy and resulting film properties are highlighted.