Synthesis and characterization of nanostructured gallium nitride PMMA composite

Nanostructured gallium nitride (GaN) was prepared by the decomposition of a dimeric precursor, Ga-2[N(CH3)(2)](6). The resulting grayish solid exhibited X-ray diffraction peaks at 2 theta = 35.5 degrees, 58 degrees, and 69 degrees, corresponding, respectively, to the (111), (220), and (311) lattice planes of face-centered cubic (zincblende) GaN. High-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 large secondary particles, which were de-agglomerated using sonication. This process yielded single-crystal particles, which were dispersed in poly(methyl methacryate) (PMMA). The particle size was 5.5 +/- 2.6 nm and the loading was approximately 9 mg/ml. The composites have a strong optical resonance in the blue region, at similar to 320 nm. (C) 1997 Acta Metallurgica Inc.