ABSTRACT
The III-nitride semiconductors have become one of the most important semiconductors in the world due to the rapid growth of solid state lighting, laser, and power electronic applications. The III-nitride semiconductor materials are basically wurtzite structures, with hexagonal symmetrical properties. Except the bandgap issues, the wurtzite nitride-based material is also the polar material. The characterization of AlN, GaN, and InN bulk material has been calculated and understood well. However, when these materials are grown under the strain condition, the band structure will be modified due to the strain. The wideband material such as GaN and AlN are very potential candidates for high power and high-frequency transistor. Due to the wide bandgap, the breakdown electric field of GaN could be at least higher than 3 MV/cm. AlGaN/GaN heterojunction field effect transistor has attracted significant attention due to their potential in high-power applications.
