Phonon spectrum of wurtzite GaN and AlN

Structure and properties of GaNxOy films grown by nitridation of GaAs (100) substrates

“…At high defect densities wave-vector conservation in the Raman scattering process breaks down and phonons from the entire Brillouin zone can be observed in the Raman spectrum. The GaN x O y films spectra show a band at 420 cm À1 and quite intense and broad bands down to 75 cm À1 : Similar bands have also been reported for ion-assisted deposited amorphous GaN [18] and Er 3þ -doped GaN films [19]. They have been correlated to the wurtzite GaN vibrational density of states as every mode can contribute to the Raman spectrum when the wave-vector selection rule is relaxed.…”

Disorder-Activated Scattering and Two-Mode Behavior in Raman Spectra of Isotopic GaN and AlGaN

“…Recalling that the B 1 low (B 1 high ) mode is dominated by the vibration of the Ga (N) atom [8], our results strongly support the assignments already proposed in Ref. [1].…”

“…The nature of such Raman features, which are forbidden by basic selection rules in ideal crystals, is still controversial. Davydov et al have investigated ion-implanted GaN and have compared their results with a theoretical phonon density of states (PDOS) [1]. Experimentally, they found new features after ion implantation and have attributed these lines to forbidden scattering by acoustic zone-boundary phonons and the silent B 1 modes.…”

Amorphous GaN Grown by Room Temperature Molecular Beam Epitaxy

“…Only Raman spectra of poly/nanocrystalline GaN have been reported so far. 7,8) GaN films were grown at room temperature and, for comparison, at 340 • C on unetched GaAs(001) substrates, i.e., on the oxide layer of GaAs substrates using a home-built 9) MBE system. An Oxford Applied Research CARS 25 activated radio frequency (RF) plasma source was used for the production of atomic nitrogen.…”