Luminescence of dimethylgallium(III) azide.

Dimethylgallium azide (Me2GaN3) and other organogallium azide compounds have attracted recent attention as potential single source precursors for the Chemical Vapor Deposition (CVD) of GaN semiconductor films.1-7 Gallium nitride is important for applications in near-UV solid-state devices such as high brightness blue LEDs and lasers. As part of our interest in the application of single source precursors for laser-assisted CVD,8-11 we investigated the excited-state properties of Me2GaN3. Solid-state Raman and Infrared studies reported that the molecule consists of trimeric subunits.12,13However, a recent X-ray crystallographic structure shows that dimethylgallium azide is a polymer in the solid state containing low molecular symmetry monomeric subunits.1 During the course of our studies of Me2GaN3, we observed luminescence from both the solid and from solutions. Emission spectra from a few metal azido complexes have been reported,14-18 but luminescence from organogallium compounds is not known. In this Note, we report the luminescence, excitation, and absorption spectra of Me2GaN3 as the polycrystalline solid and in frozen glasses and solution. Surprisingly, the luminescence spectra from the solid and solution are very similar. Raman vibrational spectra show that the species in the solid and in solution are also very similar. The spectra, the nature of the species in solution, and the assignment of the lowest energy excited state are discussed. Experimental Section