Group Ill-Nitrides semiconductor materials, including GaN, InN, A1N, InGaN, AlGaN and AlInGaN, i.e. (Al, In, Ga)N, are excellent semiconductors, covering the spectral range from UV to visible and to infrared, with unique properties very suitable for modern electronic and optoelectronic applications. Remarkable breakthroughs have been achieved in recent years for research and development (R&D) in these materials and devices, such as high-power and high-brightness blue-green-white light emitting diodes (LEDs) and blue laser diodes (LDs) as well as other optoelectronics and electronics devices and applications. III-Nitrides-based industry is forming up and new economic developments from these materials are promising. It is expected that III Nitrides- based LEDs might replace the traditional light bulbs to realize a revolution in lightings and change the entire human life in this century, similar to Edison's invention of the electric light bulb more than one hundred years ago.