The Photoelectric Properties of Gallium Nitride Materials and Applications in Semiconductor Lasers

Gallium nitride (GaN) wide bandgap devices generally have a low dielectric constant, high electron mobility, and a large bandgap. GaN is a common III-V material that has been widely used in the fabrication of electronic and optical devices such as light-emitting diodes (LEDs), lasers, and HEMTs. GaN photodetectors(PDs) are also widely used in the ultraviolet region for environmental monitoring, ultraviolet (UV) curing, etc. This article emphasizes the optoelectronic properties and semiconductor applications of GaN. GaN optoelectronic properties can be divided into three categories. The first one is band structure, which includes direct bandgap and wide bandgap (about 3.4 eV); the second one is optical properties, such as high luminous efficiency (for short wavelength emission) and absorption coefficient; the third one is electrical properties, mainly involving high breakdown field and high electron mobility (for high power devices). In addition, we discuss the application of GaN in semiconductor lasers by three different approaches. The first category is GaN-based laser structures; the second category is the application of GaN in semiconductor lasers, including blue/ultraviolet lasers and high-power lasers. Finally, we discuss challenges and advantages. Short wavelength, high efficiency, and good stability are mentioned as advantages in this section; material defects, cost, and thermal management are mentioned as disadvantages.