Group III-V Nitride semiconductors, especially gallium nitride (GaN), are very promising materials for high-power and high-frequency applications due to its outstanding properties such as a high breakdown field in wide-band gap semiconductor materials and a high saturation electron velocity. A number of GaN-based devices such as light-emitting diodes [LEDs], laser diodes [LDs], Solar-blind MSM-photodetectors, metal-semiconductor field effect transistor [MESFETs], heterostructure field-effect transistors [HFETs] and high electron mobility transistors [HEMTs] have been reported. However, larger...