AB-INITIO STUDY OF ATOMIC GEOMETRY, ELECTRONIC STATES, AND BONDING FOR H2S ADSORPTION ON III-V SEMICONDUCTOR (110)-(1X1) SURFACES

Ab initio calculations, based on pseudopotentials and the density-func tional theory, have been made to investigate the equilibrium atomic ge ometry, electronic states, and bonding of the H2S molecule on the InP( 110), GaAs(110), and GaP(110) surfaces within a dissociative adsorptio n model. In general, the adsorption of H2S on the three semiconductors shows similar behavior. The calculated average distances between the topmost InP, GaAs, and GaP layer and the sulfur atom are 1.87, 1.67, a nd 1.65 Angstrom, respectively. in all the cases studied here, the fun damental band gap is free of surface states, with an occupied surface stare close to the valence-band maximum. The calculated electronic sta tes are in agreement with reported angle-resolved photoemission data. [S0163-1829(98)04208-8].