Structural characterization of a dimeric dimethylindium azide and its use as a single-source precursor for InN thin films

Dimeric dimethylindium azide, [Me2In(μ-N3)]2 (1), was prepared from the reaction of Me3In with HN3. A single-crystal X-ray diffraction study reveals that 1 exists as a three-dimensional network of three symmetry-independent azide-bridged, centrosymmetric dimers. In each dimer, the two azido groups lying in the same plane of the (In–N)2 ring have a linear geometry, and the two indium atoms exhibit a distorted octahedral geometry. InN thin films were grown with 1 on Si(111) substrates in the temperature range 350–450°C in the absence of carrier gas by a low-pressure chemical vapor deposition method. The stoichiometry of the resulting films was determined by X-ray photoelectron spectroscopy (XPS). The films are nitrogen-deficient InN (In:N≈1:0.60) with high surface impurity concentrations (C ≈20%, O ≈27%). The film structure was examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The films appear to be polycrystalline and show diffraction patterns characteristic of the expected hexagonal wurtzite structure.