Semiconductor materials have been studied intensively since the birth of silicon technology more than 50 years ago. The ability to physically and chemically t- lor their properties with precision is the key factor responsible for the electronic revolution in our society over the past few decades. Semiconductor material s- tems (like silicon and GaAs-related materials) have now matured and found well established applications in electronics, optoelectronics, and several other ?elds. Other materials such as III-Nitrides were developed later, in response to needs that the above mentioned semiconductors were unable to ful?ll. The properties of I- nitrides (AlN, GaN InN, and related alloy systems) make them an excellent choice for ef?cient light emitters in the visible as well as the UV region, UV detectors, and for a variety of electronic device such as high frequency unipolar power devices. There was a major upsurgein the research of the GaN material system around1970.

Semiconductor materials have been studied intensively since the birth of silicon technology more than 50 years ago. The ability to physically and chemically t- lor their properties with precision is the key factor responsible for the electronic revolution in our society over the past few decades. Semiconductor material s- tems (like silicon and GaAs-related materials) have now matured and found well established applications in electronics, optoelectronics, and several other ?elds. Other materials such as III-Nitrides were developed later, in response to needs that the above mentioned semiconductors were unable to ful?ll. The properties of I- nitrides (AlN, GaN InN, and related alloy systems) make them an excellent choice for ef?cient light emitters in the visible as well as the UV region, UV detectors, and for a variety of electronic device such as high frequency unipolar power devices. There was a major upsurgein the research of the GaN material system around1970.