Gallium nitride (GaN) has been prepared by the reaction of ammonia with three different
gallium precursors: Gallium oxide, a mixture of gallium oxide and elemental gallium, and
elemental gallium. X-ray diffraction indicates that all three starting materials yield highly
crystalline wurtzite GaN particles. Solid-state 1H NMR has been employed to ascertain the
presence of hydrogen in the samples. The technique allows a clear distinction between
structural protons and protons bound to the surface of the crystals. In addition, solid-state
71Ga NMR and energy-dispersive X-ray analysis display significant differences in the
material. Depending on the starting material, the GaN product consists of up to three
different phases. The optical properties of the product GaN powders could be correlated to
the NMR data. By converting nonluminescing GaN prepared from gallium oxide into GaN,
with a bright emission at room temperature around 370 nm when excited by a 325 nm He−Cd
laser, further insight was gained on the correlation of structural and optical properties of
GaN.