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The interactions of antimony and bismuth with gallium arsenide {111} surfaces

McGinley, Colm (1998) The interactions of antimony and bismuth with gallium arsenide {111} surfaces. PhD thesis, Dublin City University.

Four Group V-GaAs{lll}-(2x2) surfaces were studied by Low Energy Electron Diffraction (LEED) and Photoelectron Spectroscopy (PES). The growth modes of these systems were established as Volmer-Weber growth for both Bi and Sb on GaAs(lll)B and Stranski-Krastanov for Sb and Bi on GaAs(lll)A. Deposition of Bi on GaAs(lll)B had the effect of removing some of the As trimers of the clean surface but this effect was not found for Sb deposition. For Bi deposition on GaAs(lll)A, a new chemical environment was found for the surface Ga. This is evidence for a Ga-Bi chemical bond, in contrast to Sb on GaAs(lll)A, where the Sb bonds to the As. These results are inferred rom core level photoelectron spectroscopy. A series of anneals was performed for each system over the temperature range for which the adsorbed layer remained on the surface. Bi fully desorbed from the GaAs(lll)A surface at 425°C and from the GaAs(lll)B surface at 475°C. In the case of Sb, desorption was complete at 600°C for both GaAs(lll)A and ( ll l)B . After desorption of both Sb and Bi overlayers from GaAs(lll)A, the (2x2) symmetry of the clean surface was regained. The GaAs(lll)B surface was faceted after Sb desorption and for Bi desorption the symmetry increased to ( lx l) . Temperature induced changes in the crystal symmetry of the adsorbate systems were followed using LEED. New surface reconstructions observed were Sb\GaAs(lll)A- (2V3x2V3)R30° [500°C-550°C], Sb\GaAs(lll)B-i3 _1} [475°C-550°C] and Bi\GaAs(lll)B-c(4x2) [110°C-375°C]. Structural models for these reconstructed systems, which take photoemission evidence for the chemical bonding into account, were derived in agreement with the electron counting rule. LEED pattern simulations were demonstrated for two of these structural models. For Bi-GaAs(lll)A, the (2x2) symmetry of the original clean surface remained for the whole experiment. Changes in the surface band bending for each system were also measured.
Item Type:Thesis (PhD)
Date of Award:1998
Supervisor(s):Cafolla, Attilio A.
Uncontrolled Keywords:Thin films; Gallium arsenide semiconductors
Subjects:Physical Sciences > Thin films
DCU Faculties and Centres:DCU Faculties and Schools > Faculty of Science and Health > School of Physical Sciences
Use License:This item is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 3.0 License. View License
ID Code:19038
Deposited On:28 Aug 2013 14:03 by Celine Campbell . Last Modified 04 Oct 2013 15:09

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