Münster 1997 – scientific programme
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HL: Halbleiterphysik
HL 5: Raman/Nichtlineare Optik
HL 5.5: Talk
Monday, March 17, 1997, 11:30–11:45, H4
MicroRaman Scattering Study of Surface-Related Phonon Modes in Porous GaP — •I.M. Tiginyanu1, G. Irmer2, J. Monecke2, and H.L. Hartnagel3 — 1Institute of Applied Physics, Academy of Sciences of Moldova, 277028 Kishinev, Moldova — 2Institut f"ur Theoretische Physik, TU Bergakademie Freiberg, B.-v.-Cotta-Str. 4, 09596 Freiberg — 3Institut f"ur Hochfrequenztechnik, Technische Hochschule Darmstadt, D-64283 Darmstadt
Porous GaP layers prepared by electrochemical dissolution of (100)-oriented bulk material have been studied by microRaman spectroscopy. The anodization causes a breakdown of the polarization selection rules, inherent to a (100)-surface, accompanied by a downward shift of the LO-phonon frequency and by the appearance of a surface-related vibrational mode in the gap between the bulk optical phonons. The frequency of the surface-related mode was found to decrease from 398 to 394.3 cm−1 with increasing anodization current. With the results of a Raman line-shape analysis based on the effective dielectric function of a composite the mode is interpreted as a Fr"ohlich mode.