Electronic structure of partially hydrogenated Si(100)-(2 x 1) surfaces prepared by thermal and nonthermal desorption

The electronic structure of partially hydrogenated Si(100)-(2 X 1) surfaces , prepared by controlled thermal annealing and nonthermal photon stimulated desorption of fully hydrogenated Si(100) surfaces, has been investigated b y using valence band photoemission. Thermal and nonthermal desorption are f ound to produce very specific electronic surface structures. This led us to the discovery of two specific surface states having binding energies of 1. 0 and 0.7 eV associated with the isolated Si dimers and single Si dangling bonds, respectively.