A cluster approach to hydrogen chemisorption on the GaAs(100) surface

Chemisorption properties of atomic hydrogen on the Ga-rich GaAs(100), (2 x 1) and P(4 x 2) surfaces are investigated using ab initio self-consistent r estricted open shell Hartree-Fock (ROHF) total energy calculations with Hay -Wadt (HW) effective core potentials. The effects of electron correlation h ave been included using many-body perturbation theory through second order with the exception of beta (4 x 2) symmetry due to computational limitation s. The semiconductor surface is modeled by finite sized hydrogen saturated clusters. The effects of surface reconstruction have been investigated in d etail. We report on the energetics of chemisorption on the (100) surface la yer, including adsorption beneath the surface layer at an interstitial site , and also report on the possible dimer bond breaking at the bridge site. C hemisorption energies, bond lengths, and charge population analysis are rep orted for all considered sites of chemisorption. (C) 2001 Elsevier Science B.V. All rights reserved.