https://doi.org/10.1007/s100510070241
HREELS investigation of hydrogenated and deuterated GaN{0001} surfaces
Laboratorium für Festkörperphysik, Gerhard-Mercator-Universität Duisburg,
47048 Duisburg, Germany
Corresponding author: a sgrabowski@uni-duisburg.de
Received:
1
February
2000
Published online: 15 July 2000
The vibrational properties of clean, H- and D-covered GaN{0001} surfaces were investigated by high-resolution electron energy-loss spectroscopy. Auger electron spectroscopy and low-energy electron diffraction were utilized to monitor the surface cleanliness and structure, respectively. At the clean surface the Fuchs-Kliewer surface phonon frequency was determined to 700 cm-1 (86.8 meV). For the adsorbate-covered surfaces current structure models predict only Ga-H vibrations for surfaces of either polarity. Despite of this, the HREEL-spectra of the hydrogenated sample show a new loss structure at 3255 cm-1 (403.6 meV) and a shoulder at 1900 cm-1 (235.6 meV) which are attributed to N-H and Ga-H stretching vibrations, respectively. After deuterium exposure an isotope shift occurs. Again, a N-adsorbate vibration is clearly resolved. A Ga-D bending mode is observed at 390 cm-1 (48.4 meV), indicating that vibrations of both species are present.
PACS: 82.65.My – Chemisorption / 68.35.Ja – Surface and interface dynamics and vibrations / 79.20.-m – Impact phenomena (including electron spectra and sputtering)
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2000
