ABSTRACT
Research and development on advanced semiconductors, especially wide energy gap GaN-, SiC-, and ZnO-based, various oxides, related materials, and quantum/nano structures, have been very extensive in recent years. Energy-ef‹cient and environmentally friendly solid-state light sources, in particular GaN-based light-emitting diodes (LEDs) and solar cells, are currently revolutionizing an increasing number of applications, and bring apparent bene‹ts to vast areas of development, such as lighting, communications, biotechnology, imaging, energy conversion, photovoltaic, and medicine [1,2]. It is expected that LEDs may replace traditional light bulbs and tubes to achieve a new lighting echo. Solar cells may gradually increase their share in energy production. SiC is recognized as a powerful electronic materials for the twenty-‹rst century [3,4]. Zinc oxide (ZnO) is rapidly rising as the third class of promising wide-gap semiconductor. New oxides and compound semiconductors are developing amazingly, which may also be incorporated into the aforementioned energy-saving devices.
