The chemisorption of atomic hydrogen on the silicon (111) 7 × 7 surface has been studied using ionneutralization spectroscopy and ultraviolet-photoemission spectroscopy with the help of low-energy electron diffraction and work-function measurement. Both spectroscopies showed that the dangling-bond surface state disappears when the clean surface is exposed to atomic hydrogen. Chemisorbed hydrogen produces two sharp peaks in the surface density of states at approximately -10 and -12 eV from the vacuum level. These results are in good quantitative agreement with the recent theoretical works by Appelbaum and Hamann and by Pandey.

• Received 28 July 1975

DOI:https://doi.org/10.1103/PhysRevB.12.5349