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Photoemission from alpha and beta phases of the GaAs(001)-c(4 x 4) surface

Jiricek, P.; Cukr, M.; Bartos, I. and Sadowski, Janusz LU (2009) In Surface Science 603(20). p.3088-3093
Abstract
We prepared alpha- and beta surface phases of GaAs(0 0 1)-c(4 x 4) reconstruction by molecular beam epitaxy (MBE) using As-4 and As-2 molecular beams, respectively, and examined them by angle-resolved ultraviolet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS) with synchrotron radiation as an excitation source. The UPS valence band spectra and the XPS 3d core level data show pronounced differences corresponding to the surface composition and the atomic structure of the two phases, as proposed in the literature. In UPS, the beta phase is characterized by an intensive surface state 0.5 eV below the top of the valence band at low photon energy, while an analogous peak in the alpha phase spectra is missing. The... (More)
We prepared alpha- and beta surface phases of GaAs(0 0 1)-c(4 x 4) reconstruction by molecular beam epitaxy (MBE) using As-4 and As-2 molecular beams, respectively, and examined them by angle-resolved ultraviolet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS) with synchrotron radiation as an excitation source. The UPS valence band spectra and the XPS 3d core level data show pronounced differences corresponding to the surface composition and the atomic structure of the two phases, as proposed in the literature. In UPS, the beta phase is characterized by an intensive surface state 0.5 eV below the top of the valence band at low photon energy, while an analogous peak in the alpha phase spectra is missing. The surface state is interpreted in terms of dangling bonds on As dimers. The As3d and Ga3d core level photoelectron lines exhibit phase-specific shapes as well as differences in the number, position and intensity of their deconvoluted components. The location of various atoms in the surface and subsurface layers is discussed; our photoemission results support models of the beta phase and the alpha phase with As-As dimers and Ga-As heterodimers, respectively. (C) 2009 Elsevier B.V. All rights reserved. (Less)
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author
organization
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type
Contribution to journal
publication status
published
subject
keywords
shift, Surface core level, Molecular beam epitaxy, photoelectron spectroscopy, Synchrotron radiation, Gallium arsenide, Angle resolved photoemission, Surface phase
in
Surface Science
volume
603
issue
20
pages
3088 - 3093
publisher
Elsevier
external identifiers
  • wos:000271179600009
  • scopus:70349630422
ISSN
0039-6028
DOI
10.1016/j.susc.2009.08.021
language
English
LU publication?
yes
id
99ff57f9-b170-4e02-ad56-b41d74670759 (old id 1505262)
date added to LUP
2009-11-24 13:39:17
date last changed
2017-01-01 06:31:25
@article{99ff57f9-b170-4e02-ad56-b41d74670759,
  abstract     = {We prepared alpha- and beta surface phases of GaAs(0 0 1)-c(4 x 4) reconstruction by molecular beam epitaxy (MBE) using As-4 and As-2 molecular beams, respectively, and examined them by angle-resolved ultraviolet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS) with synchrotron radiation as an excitation source. The UPS valence band spectra and the XPS 3d core level data show pronounced differences corresponding to the surface composition and the atomic structure of the two phases, as proposed in the literature. In UPS, the beta phase is characterized by an intensive surface state 0.5 eV below the top of the valence band at low photon energy, while an analogous peak in the alpha phase spectra is missing. The surface state is interpreted in terms of dangling bonds on As dimers. The As3d and Ga3d core level photoelectron lines exhibit phase-specific shapes as well as differences in the number, position and intensity of their deconvoluted components. The location of various atoms in the surface and subsurface layers is discussed; our photoemission results support models of the beta phase and the alpha phase with As-As dimers and Ga-As heterodimers, respectively. (C) 2009 Elsevier B.V. All rights reserved.},
  author       = {Jiricek, P. and Cukr, M. and Bartos, I. and Sadowski, Janusz},
  issn         = {0039-6028},
  keyword      = {shift,Surface core level,Molecular beam epitaxy,photoelectron spectroscopy,Synchrotron radiation,Gallium arsenide,Angle resolved photoemission,Surface phase},
  language     = {eng},
  number       = {20},
  pages        = {3088--3093},
  publisher    = {Elsevier},
  series       = {Surface Science},
  title        = {Photoemission from alpha and beta phases of the GaAs(001)-c(4 x 4) surface},
  url          = {http://dx.doi.org/10.1016/j.susc.2009.08.021},
  volume       = {603},
  year         = {2009},
}