Self organization of nitride quantum dots by molecular beam epitaxy

Taking adavantage of the Stranski-Krastanov growth mode of GaN deposited on AlN, the formation of self-organized GaN islands has been achieved in both hexagonal and cubic phases. It has been shown that the dot size variation as a function of time obeys an Ostwald's ripening mechanism. Vertical correlation effects between stacked layers of dots have been shown to result in a better size homogeneity and a decrease in density. The optical properties of the GaN dots have been studied by photoluminescence. A blue shift is oberved which is definitely assigned to quantum confinement effects. (C) 1999 Elsevier Science S.A. All rights reserved.