Plasma assisted molecular beam epitaxy growth of GaN

The growth of GaN on sapphire by plasma assisted molecular beam epitaxy (MBE) is investigated with the object of optimizing the material quality. The V/III flux ratio as well as the growth temperature are discussed in relation to their impact on electrical, optical and structural layer properties. Samples grown under nearly stoichiometric conditions exhibit both the highest mobilities and the highest photoluminescence efficiencies. Growth temperatures above 800°C were found to result in narrow reflections in X-ray diffraction. However, the chemical decomposition of GaN at temperatures above 850°C limits the suitable temperature range for the growth under high vacuum conditions.