Micro-Raman Investigation of Nanocrystalline GaN, AlN, and an AlGaN Composite Prepared from Pyrolysis of Metal Amide-Imide Precursors

In this communication, the impact of precursor pyrolysis temperature on the Raman spectroscopic properties of nanophase GaN derived from the polymeric gallium imide GaNH32n is reported. GaN prepared by pyrolysis at either 900 or 1100 deg C exhibit modes at approx. 570 and 730 cm consistent with the presence of hexagonal GaN. Employing a lower conversion temperature of 700 deg C produces a lattice with extensive defects, as evidenced by the prescence of additional bands at 332, 410, 637, and 744 cm additional heating of this type of sample at 900 and 1000 deg C diminishes the intensity of these defect-related modes. Raman spectra of nanophase aluminum nitride AlN and an aluminum gallium nitride AlGaN composite prepared from pyrolysis of the requisite precursors at a fixed temperature of 900 deg C are also presented.