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Presents information on a study which investigated the sapphire nitridation temperature as possible parameter to improve the properties of gallium nitride (GaN) epilayers grown by molecular beam epitaxy. Experimental details; Results and discussion; Influence of the nitridation temperature on the properties of GaN layers; Conclusions.

Studies the vibration modes of gallium nitride-AlN superlattice grown by molecular beam epitaxy on a sapphire substrate and an AlN buffer layer by micro-Raman spectroscopy. Frequency shift of phonons; Average strain value in GaN layers; Strain relaxation percentage of GaN layers lying close to the interface with the buffer layer.

The surfactant effect of In during the growth of GaN by molecular beam epitaxy has been investigated. It has been found that the presence of In modifies the diffusion kinetics in the growing GaN surface, leading to the observation of persistent reflection high energy electron diffraction intensity oscillations, characteristic of layer-by-layer growth. Electron microscopy studies revealed drastic modifications of the GaN structural properties associated with the presence of In during the growth. When grown in the presence of In, GaN exhibits an intense band edge luminescence, free of the component at 3.41 eV which is characteristic of defects associated with growth in N-rich conditions. © 1998 American Institute of Physics. [ABSTRACT FROM AUTHOR]