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Optical second harmonic generation study of vicinal Si(111) surfaces
A337 462
Surface Science 251/252 (1991) 462-466 North-Holland
Initial formation of the CaF~ interface: a theoretical study S. Ossicini, C. Arcangeli Dipartimento di Fisica della UniversitY, Via Campi 213/A, 1-41100 Modena, Italy
and O. Bisi Dipartimento di Fisica della Universit& Pant~ di Povo, 1-38050 Trento, Italy Received 1 October 1990; accepted for publication 23 November 1990 The insulator-semiconductor CaF2-Si(lll ) interface is studied in the first stages of formation. The linear muffin-tin orbitals method in the atomic-sphere approximation is employed to investigated the F - C a - S i ( l l l ) interface. The analysis of both valence and core electron states gives information about the nature of the bond between Ca, F and Si surface and allows one to interpret the available experimental data.
Surface Science 251/252 (1991) 467-471 North-Holland
467
Optical second harmonic generation study of vicinal Si(lll) surfaces M.A. Verheijen, C.W. van Hasselt and Th. Rasing Research Institute for Materials, University of Nijmegen, Toernooioeld, 6525 ED Nijmegen, Netherlands Received 1 October 1990; accepted for publication 23 November 1990 The appearance of well defined steps on vicinal Si(lll) surfaces has a very pronounced effect on the rotational anisotropy of the Second Harmonic Generation from these surfaces. This effect can be explained by the lowering of the surface symmetry and an enhancement of the nonlinear susceptibility at these steps. By modifying the surface in this way, surface and bulk contributions to the SHG could be determined separately.
472
Surface Science 251/252 (1991) 472-477 North-Holland
Interface chemistry and band bending induced by Pt deposition onto GaP(110) Th. Chass~ 1, W. Theis, T.P. Chen, D.A. Evans, K. Horn Fritz-Haber-lnstitut der Max-Planck-Gesellschaft, W-IO00 Berlin 33, Germany
C. Pettenkofer and W. Jaegermann Hahn-Meitner-Institut, Ve'.IO00 Berlin 39, Germany Received 1 October 1990; accepted for publication 16 December 1990 The P t / G a P ( l l 0 ) interface has been studied by core and valence level photocmission using synchrotron radiation. The results are characteristic of a reactive interface, where the GaP substrate is disrupted by the deposited platinum layer resulting in an increasing reacted Ga emission and a strong attenuation of the substrate Ga emission. The detailed analysis of band bending shows that Pt, being a high work-function material, nevertheless has a final pinning position which is close to that of other materials. The value for the Schottky barrier inferred from the photoemission data, • 4 is 1.56 eV. We observe a distortion of the equilibrium band arrangement by the incident photons, giving rise to a surface photovoltage even at room temperature. This effect can strongly influence the determination of surface band bending.
Surface Science 251/252 (1991) 462-466 North-Holland
Initial formation of the CaF~ interface: a theoretical study S. Ossicini, C. Arcangeli Dipartimento di Fisica della UniversitY, Via Campi 213/A, 1-41100 Modena, Italy
and O. Bisi Dipartimento di Fisica della Universit& Pant~ di Povo, 1-38050 Trento, Italy Received 1 October 1990; accepted for publication 23 November 1990 The insulator-semiconductor CaF2-Si(lll ) interface is studied in the first stages of formation. The linear muffin-tin orbitals method in the atomic-sphere approximation is employed to investigated the F - C a - S i ( l l l ) interface. The analysis of both valence and core electron states gives information about the nature of the bond between Ca, F and Si surface and allows one to interpret the available experimental data.
Surface Science 251/252 (1991) 467-471 North-Holland
467
Optical second harmonic generation study of vicinal Si(lll) surfaces M.A. Verheijen, C.W. van Hasselt and Th. Rasing Research Institute for Materials, University of Nijmegen, Toernooioeld, 6525 ED Nijmegen, Netherlands Received 1 October 1990; accepted for publication 23 November 1990 The appearance of well defined steps on vicinal Si(lll) surfaces has a very pronounced effect on the rotational anisotropy of the Second Harmonic Generation from these surfaces. This effect can be explained by the lowering of the surface symmetry and an enhancement of the nonlinear susceptibility at these steps. By modifying the surface in this way, surface and bulk contributions to the SHG could be determined separately.
472
Surface Science 251/252 (1991) 472-477 North-Holland
Interface chemistry and band bending induced by Pt deposition onto GaP(110) Th. Chass~ 1, W. Theis, T.P. Chen, D.A. Evans, K. Horn Fritz-Haber-lnstitut der Max-Planck-Gesellschaft, W-IO00 Berlin 33, Germany
C. Pettenkofer and W. Jaegermann Hahn-Meitner-Institut, Ve'.IO00 Berlin 39, Germany Received 1 October 1990; accepted for publication 16 December 1990 The P t / G a P ( l l 0 ) interface has been studied by core and valence level photocmission using synchrotron radiation. The results are characteristic of a reactive interface, where the GaP substrate is disrupted by the deposited platinum layer resulting in an increasing reacted Ga emission and a strong attenuation of the substrate Ga emission. The detailed analysis of band bending shows that Pt, being a high work-function material, nevertheless has a final pinning position which is close to that of other materials. The value for the Schottky barrier inferred from the photoemission data, • 4 is 1.56 eV. We observe a distortion of the equilibrium band arrangement by the incident photons, giving rise to a surface photovoltage even at room temperature. This effect can strongly influence the determination of surface band bending.