OPTICAL AND MICROSTRUCTURAL CHARACTERIZATION OF CHEMICALLY SYNTHESIZED GALLIUM NITRIDE NANOPOWDERS

Thermal decomposition of an amido precursor; [Ga-2(NMe2)(6), Me=CH3] i n an ammonia atmosphere yielded nanostructured gallium nitride powder. The x-ray diffraction spectrum of the nanosized gallium nitride exhib ited reflections corresponding to the lattice planes of fee (zinc blen de) GaN. High resolution transmission electron microscopy confirmed th e cubic structure of the material and evidence of stacking faults with in the fee structure. Infrared spectra showed the characteristic Ga-N stretch at 550 cm(-1). Transmission electron microscope measurements i ndicated that the GaN consisted of approximate to 50 nm sized particle s which in turn are agglomerates of smaller particles with approximate to 5 nm domain sizes. The photoluminescence (PL) emission spectrum of the GaN was found to be sensitive to the excitation wavelength exhibi ting peaks at 378 and 317 nm. The PL excitation spectrum showed resona nces in the 200-300 nm region. These PL results suggest the effect of quantum confinement in these GaN particles. (C) 1997 American Institut e of Physics.