Surface vibrations on clean, deuterated, and hydrogenated single crystal diamond(100) surfaces studied by high-resolution electron energy loss spectroscopy

Abstract

We present a detailed study of the clean, hydrogenated, and deuterated (2×1)-reconstructed (100) surface of diamond by angular dependent high-resolution electron energy loss spectroscopy (HREELS). We were able to identify two Rayleigh modes on all surfaces. The measured dispersion widths for the two modes are 40 meV and 43 meV on the clean diamond surface. On the hydrogenated and the deuterated surface the same dispersion widths are measured, namely 43 meV and 60 meV, indicating that no isotope shift is observed for the Rayleigh modes between these two surfaces. Bending modes could be assigned to structures at 119 meV and 183 meV for the hydrogen covered and to those at 87 meV and 137 meV on the deuterated surface. Moreover, on the clean surface modes at 180 meV and 93 meV are ascribed to the dimer stretch or dimer twist and the dimer bounce vibration, respectively.