SYNTHESIS AND CHARACTERIZATION OF NANOSTRUCTURED GALLIUM NITRIDE PMMACOMPOSITE

Nanostructured gallium nitride (GaN) was prepared by the decomposition of a dimeric precursor, Ga-2[N(CH3)(2)](6). The resulting grayish sol id exhibited X-ray diffraction peaks at 2 theta = 35.5 degrees, 58 deg rees, and 69 degrees, corresponding, respectively, to the (111), (220) , and (311) lattice planes of face-centered cubic (zincblende) GaN. Hi gh-resolution transmission electron microscopy (HRTEM) showed that the material was fcc, with numerous stacking faults. The GaN consisted of primary domains of five nanometers diameter which agglomerated into l arge secondary particles, which were de-agglomerated using sonication. This process yielded single-crystal particles, which were dispersed i n poly(methyl methacryate) (PMMA). The particle size was 5.5 +/- 2.6 n m and the loading was approximately 9 mg/ml. The composites have a str ong optical resonance in the blue region, at similar to 320 nm. (C) 19 97 Acta Metallurgica Inc.