TY - JOUR
T1 - Observation of surface polarity dependent phonons in SiC by deep ultraviolet Raman spectroscopy
AU - Nakashima, S.
AU - Mitani, T.
AU - Tomita, T.
AU - Kato, T.
AU - Nishizawa, S.
AU - Okumura, H.
AU - Harima, H.
PY - 2007/3/23
Y1 - 2007/3/23
N2 - Backscattering Raman spectra of SiC polytype crystals with SiC{0001} polar faces have been measured using deep ultraviolet (DUV), UV, and visible (VIS) excitation sources. We have found that for DUV excitation the intensity profiles of zone-folded modes differ markedly for Si and C faces. This Raman spectral feature is attributed to the presence of nonpropagating phonon modes confined in the near-surface region. It is concluded that the surface-bound phonon modes created with DUV photon field extend over a region a few hundred nanometers in depth, and that the displacements of the phonon modes are anisotropic in the direction of the polar axis. This surface-orientation-dependent Raman spectrum can be used to identify the surface polarity of SiC polytypes.
AB - Backscattering Raman spectra of SiC polytype crystals with SiC{0001} polar faces have been measured using deep ultraviolet (DUV), UV, and visible (VIS) excitation sources. We have found that for DUV excitation the intensity profiles of zone-folded modes differ markedly for Si and C faces. This Raman spectral feature is attributed to the presence of nonpropagating phonon modes confined in the near-surface region. It is concluded that the surface-bound phonon modes created with DUV photon field extend over a region a few hundred nanometers in depth, and that the displacements of the phonon modes are anisotropic in the direction of the polar axis. This surface-orientation-dependent Raman spectrum can be used to identify the surface polarity of SiC polytypes.
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U2 - 10.1103/PhysRevB.75.115321
DO - 10.1103/PhysRevB.75.115321
M3 - Article
AN - SCOPUS:33947516175
VL - 75
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
SN - 1098-0121
IS - 11
M1 - 115321
ER -