Accession Number : ADA325156

Title :   New Precursor Routes to Nanocrystalline Cubic/Hexagonal Gallium Nitride, GaN.

Descriptive Note : Technical rept.,

Corporate Author : DUKE UNIV DURHAM NC DEPT OF CHEMISTRY

Personal Author(s) : Wells, R. L. ; Janik, J. F. ; Gladfelter, V. W. ; Coffer, J. L. ; Johnson, M. A.

PDF Url : ADA325156

Report Date : 15 MAR 1997

Pagination or Media Count : 9

Abstract : Two precursor routes culminating in bulk nanocrystalline gallium nitride materials are reported, with emphasis on the materials XRD/crystalline features and photoluminescence (PL). First, the new gallium imide, Ga(NH)3/2n can be converted to nanocrystalline, cubic/hexagonal GaN ranging in color from yellow to light gray. Second, a new route to gallazane, H2GaNH2x, from the combination of LiGaH4 and NH4X (X = Cl, Br) in Et(2)O is shown to result in a material that slowly converts to a polymeric solid via H2 and NH3 elimination condensation pathways. Both the gallazane and the polymeric solid are pyrolyzed to dark gray nanocrystyalline, phase-inhomogeneous GaN as above. Specific variations in the pyrolysis conditions enable some control over the particle nanosize and a degree of crystalline phase-inhomogeneity of the materials. These nanophase GaN materials have also been characterized by room temperature photoluminescence measurements. In general, the observed emission spectra are strongly dependent on pyrolysis temperature and typically exhibit weak defect yellow green emission. While the as-prepared GaN does not exhibit band-edge PL, a brief hydrofluoric acid etch yields nanophase GaN exhibiting an intense blue-emitting PL spectrum with an emission maximum near 420 nm.

Descriptors :   *PHOTOLUMINESCENCE, *SYNTHESIS(CHEMISTRY), *PYROLYSIS, *POLYCRYSTALLINE, PARTICLE SIZE, PRECURSORS, EMISSION SPECTRA, NITRIDES, ROOM TEMPERATURE, GALLIUM COMPOUNDS, IMIDES, NANOTECHNOLOGY.

Subject Categories : Industrial Chemistry and Chemical Processing
      Crystallography
      Optics
      Thermodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE