Dopant incorporation and defects in III-V nitrides and related semiconductors and their applications

Gallium Nitride and its alloys with InN and AIN have recently emerged as important semiconductor materials with applications to yellow, green, blue and ultraviolet portions of the spectrum as emitters and detectors, and high power electronic devices. Nitride LEDs exhibit brightness levels and longevity well in access of what is required for outdoor applications. Combined with the available Very LEDs, one can; for the first time, have full color all semiconductor displays. Very recently pulsed room temperature operation of 410 nm semiconductor laser, the shortest wavelength ever from a semiconductor, has been reported. If used for traffic lights, in office. automobile, aircraft, airport, run-ways, ships and home illumination, these devices can outlast and outperform the incandescent light bulbs while saving precious energy. This material system is also intrinsically germane to short wavelength semiconductor lasers for increased data storage. Nitrides are also conductive for high power devices/circuits, and sensors and detectors with applications in high temperature and unfriendly environments. Estimates show that substantial weight savings can be had in aircraft and spacecraft. In aircraft, the devices can replace the bulky hydraulics rendering the craft more reliable and lighter while avoiding costly coolers. Moreover, AlGaN alloy with bandgaps above 5.5 eV shows negative electron affinity surface with applications to cold cathodes in general and flat panel displays in particular. GaN and related materials are rich in defects? certainly to a large extent due to the lack of native substrates, whose characteristics have been analyzed both structurally and electronically. Recent data indicate that the large background electron concentrations encountered in early stages of development are due to nitrogen vacancies. The p type doping incorporation is a very complex process in that the presence of p type impurities in the growth environment can result in defect formation. However, when the conditions are favorable, the p type dopant incorporation follows the side selection criteria meaning conditions favoring Ga vacancies appear to be desirable.