Interaction of atomic hydrogen with a Ge(111) surface: low-energy electron diffraction and surface Raman studies

We report the preparation and characterization of a sufficiently ordered Ge(111)-1 × 1:H surface by prolonged hydrogenation of Ge(111)-c(2 × 8) at elevated temperatures. For both annealed and sputtered/annealed c(2 × 8) surfaces, a (1 × 1) pattern with distinct primary-order spots was observed by low-energy electron diffraction (LEED) after extensive hydrogenation treatment. We demonstrated that a surface Raman spectroscopic method based on polarization effects can be used successfully to characterize such a prepared Ge(111)-1 × 1:H surface, which is flat enough to yield a single prominent peak of the monohydride GeH stretch. The possible mechanism for surface smoothing by atomic hydrogen is also discussed. The smoothness of this surface makes various spectroscopic characterization methods feasible.