Wurtzite GaN nanocrystals were produced by the pyrolysis and crystallization of two different precursors, gallium dimethyl amide (GDA) and gallium isopropoxide (GIP), in an ammonia atmosphere between 600degreesC and 1200degreesC. Ammonia reacted with GDA at room temperature by transamination, followed by deamination of the amorphous precursor at higher temperatures. After crystallization to wurtzite GaN, grain growth occurred and was dominated by evaporation-condensation. Low-temperature pyrolysis of GIP in an ammonia atmosphere yielded gallium oxynitride nanocrystals. Higher processing temperatures transformed the nanocrystalline powders to wurtzite GaN. GaN powders exhibited the room temperature photoluminescence characteristic of wurtzite GaN. Nitrogen vacancies present in the powder appear to be potential candidates for the yellow luminescence. (C) 2002 Elsevier Science B.V. All rights reserved.