Gallium Nitride (GaN), as a new type of semiconductor material for the development of microelectronics and optoelectronic devices, along with SiC, diamond and other semiconductor materials, is hailed as the third-generation semiconductor material following the first-generation Ge, Si semiconductor materials, and the second-generation GaAs, InP compound semiconductor materials. As a representative of the third-generation semiconductor materials, GaN-based semiconductor materials are the core materials and basic devices of the emerging semiconductor optoelectronic industry. They not only bring about a revolution in digital storage technology in the IT industry, but also completely change the history of traditional human lighting, and will promote the development of communication technology.