FORMATION OF A TETRAMERIC, CYCLOOCTANE-LIKE, AZIDOCHLOROGALLANE, [HCLGAN3](4), AND RELATED AZIDOGALLANES - EXOTHERMIC SINGLE-SOURCE PRECURSORS TO GAN NANOSTRUCTURES

The synthesis of a novel tetrameric gallane, [HCIGaN3](4) (1), with a heterocyclic cyclooactane-like structure has been demonstrated. A sing le-crystal X-ray study reveals that the molecule consists of eight-mem bered Ga4N4 rings with Ga atoms bridged by the alpha-nitrogens of the azide groups. [HClGaN3](4) crystallizes in the tetragonal space group space group P4(2)bc, with a = 17.920(3) Angstrom, c = 10.782(3) Angstr om, V = 3462(2) Angstrom(3), and Z = 8. On the basis of the mass spect rum, the vapor of the compound consists of the trimer [HClGaN3](3), wh ich is a low-temperature molecular source for growth of GaN layers on sapphire and Si substrates at 500 degrees C. Solid 1 decomposes exothe rmically at 70 degrees C to yield bulk nanocrystalline wurtzite and zi nc blende GaN. The reaction between H2GaCl and LiN3 yields the analogo us and extremely simple azidogallane (H2GaN3), (2), which is used to d eposit crystalline GaN films at 450 degrees C. Compound 2 is considera bly more reactive than 1, and its decomposition, often initiated at ro om temperature, yields pure and crystalline nitride material of unusua l morphology and microstructure.