PLASMA-ASSISTED MOLECULAR-BEAM EPITAXY GROWTH OF GAN

The growth of GaN on sapphire by plasma assisted molecular beam epitax y (MBE) is investigated with the object of optimizing the material qua lity. The V/III flux ratio as well as the growth temperature are discu ssed in relation to their impact on electrical, optical and structural layer properties. Samples grown under nearly stoichiometric condition s exhibit both the highest mobilities and the highest photoluminescenc e efficiencies. Growth temperatures above 800 degrees C were found to result in narrow reflections in X-ray diffraction. However, the chemic al decomposition of GaN at temperatures above 850 degrees C limits the suitable temperature range for the growth under high vacuum condition s. (C) 1997 Elsevier Science S.A.