Reconstruction of semiconductor surfaces was considered in a tight-binding framework using the bond orbital approximation to simplify the total energy calculation. A Jahn-Teller type of distortion, based upon a dehybridization of the dangling hybrids, was found to dominate and to lead to distortions larger than those customarily proposed at surfaces. This result, together with experimental knowledge of the surfaces, led to specific forms for the reconstruction expected on the principal symmetry surfaces of both polar and non-polar semiconductors. The forms found for (111) and (110) silicon surfaces were among forms which were proposed earlier, but a canted ridge structure for the (100) surface was new. The reconstruction was large enough to drop the occupied dangling hybrid state deep into the valence band, suggesting that observed structure near the top of the valence band was due to back bonds, in agreement with Pandey and Phillips. The reconstruction also tends to increase the work function above the unreconstructed value on all surfaces. The effect of adsorption of atoms on the reconstruction as a function of the valence of the adsorbate, was summarized. It was found that while the energy to form a vacancy on a silicon (111) surface was very large, silicon atoms outside the nominal surface should be quite stable. This suggested that the 7 x 7 reconstruction was a pattern of add-atoms rather than (and topologically unrelated to) a pattern of vacancies.

Surface Reconstruction on Semiconductors. W.A.Harrison: Surface Science, 1976, 55[1], 1-19