Resonance Raman scattering and lattice dynamics of GaMnN crystals
|Wojtek Gebicki 1, Pawel Dominik 2, Sławomir Podsiadło 2|
1. Warsaw University of Technology, Faculty of Physics, Koszykowa 75, Warszawa 00-662, Poland
We are presenting results of Raman scattering investigation of GaMnN crystals. The detailed study of polarization dependence Raman scattering enabled us to determine the symmetries of phonon bands characteristic for the system. It has been shown that the polarization dependence of the Raman spectra in the longtitudinal optical (LO) phonon spectral region is identical for all the peaks and suggests an impurity induced Fröhlich type resonance Raman scattering. This result is supported by measured dependence of the Raman spectra on excitation laser line. Phonon dispersion curves and density of phonon states have been calculated with use of a combination of VASP and Phonon computer codes. The phonon density of states has been compared with Raman scattering spectra. It has been shown that nitrogen vibrations are responsible for the new Raman bands observed at the LO phonon spectral region. The Mn vibrations are masked by the strong lattice bands. The role of nitrogen vacancy in lattice dynamics of the GaN:Mn system is discussed. Possible usage of the method for interpretation of the Raman spectra resulting from some other defects in GaN is suggested.
Presentation: Oral at E-MRS Fall Meeting 2008, Symposium J, by Wojtek Gebicki
See On-line Journal of E-MRS Fall Meeting 2008
Submitted: 2008-05-30 15:46 Revised: 2009-06-07 00:48