| 1. |
- Varekamp, P R, et al.
(författare)
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Reaction of I-2 with the (001) surfaces of GaAs, InAs, and InSb .1. Chemical interaction with the substrate
- 1996
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 54:3, s. 2101-2113
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Tidskriftsartikel (refereegranskat)abstract
- InAs(001)-c(8x2), InSb(001)-c(8x2), and several reconstructions of GaAs(001) are exposed at room temperature to iodine molecules (I-2). Low-energy electron diffraction (LEED) and synchrotron soft x-ray photoelectron spectroscopy (SXPS) are employed to study the surfaces as a function of I-2 dose and sample anneal. In the exposure range studied, GaAs and InAs become saturated with I-2, resulting in removal of the clean surface reconstruction and the formation of a very strong 1x1 LEED pattern. Iodine bonds primarily to the dominant elemental species present on the clean surface, whether it is a group-III or -V element. The InSb(001)-c(8x2) reconstruction is also removed by I-2 adsorption, and a strong 1x1 LEED pattern is formed. SXPS data, in conjunction with scanning tunneling microscopy images, however, reveal that InSb(001)-c(8x2) does not saturate at room temperature, but is instead etched with a preferential loss of In. Heating the iodine-covered group-III-rich InAs(001)-c(8x2) and InSb(001)-c(8x2) surfaces causes removal of the iodine overlayer and transformation to a group-V-rich reconstruction. When the iodine-covered As-rich GaAs(001)-c(2x8) surface is heated to remove iodine, however, the c(2x8) reconstruction is simply regenerated.
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| 2. |
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| 3. |
- Andersson, C B M, et al.
(författare)
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Surface atomic structure of InAs((111)over-bar)2x2 and InSb((111)over-bar)2x2 studied by core level spectroscopy
- 1996
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Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 347:1-2, s. 199-206
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Tidskriftsartikel (refereegranskat)abstract
- Surface sensitive high resolution core level spectroscopy has been applied to the molecular beam epitaxy grown InAs((111) over bar)2 x 2 and InSb((111) over bar)2 x 2 surfaces. For both systems the In 4d core level consists of one dominating component while the Group V core levels are deconvoluted into four components. This analysis is consistent with a surface model where the topmost layer consists entirely of arsenic or antimony. In this model, Group V atoms form trimers bound to Group V atoms in the first double layer, leaving a single Group V rest atom per unit cell.
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| 4. |
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| 5. |
- Hakansson, M C, et al.
(författare)
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The electronic structure of In- and As-terminated InAs(001) surfaces
- 1997
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Ingår i: Surface Science. - 0039-6028 .- 1879-2758. ; 374:1-3, s. 73-79
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Tidskriftsartikel (refereegranskat)abstract
- The InAs(001) 2 x 4 and 4 x 2 surfaces have been investigated by angle-resolved photoemission. The X(3) and X(5) points were found to be located 6.0 and 2.7 eV below the valence band maximum, respectively, and the dispersion of bulk bands along the Gamma-X direction in the bulk Brillouin zone were well described by a theoretical calculation. From angle-resolved valence band spectra measured along the high symmetry directions [110] and [1(1) over bar0$], three surface induced stares were identified on both the InAs(001)4 x 2 and the InAs(001)2 x 4 surface. (C) 1997 Elsevier Science B.V.
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| 6. |
- Olsson, L O, et al.
(författare)
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Charge accumulation at InAs surfaces
- 1996
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 76:19, s. 3626-3629
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Tidskriftsartikel (refereegranskat)abstract
- Angle-resolved photoelectron spectroscopy has been used to directly prove the existence of a charge accumulation layer at clean InAs surfaces. The formation of an accumulation layer is shown to be a common property of polar InAs surfaces, with the precise surface Fermi level position above the conduction band minimum determined by the surface geometry. The emission from states in the accumulation layer is studied with respect to its photon energy and angular dependence.
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| 7. |
- Olsson, L O, et al.
(författare)
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Core level and valence-band studies of the (111)2x2 surfaces of InSb and InAs
- 1996
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Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 53:8, s. 4734-4740
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Tidskriftsartikel (refereegranskat)abstract
- The valence and core electronic surface states on the (111)2X2 surfaces of InSb and InAs have been studied by angle-resolved photoelectron spectroscopy. Similarities in data show that the vacancy-buckling model, which is known to describe the InSb(111)2x2 surface, also applies to InAs(111)2X2. Three surface valence bands are identified and their dispersions are mapped along symmetry directions in the surface Brillouin zone. The In 4d core levels show one surface shifted component while no surface shifted components of the Sb 4d or As 3d core levels could be resolved.
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| 8. |
- Varekamp, P R, et al.
(författare)
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Reaction of I-2 with the (001) surfaces of GaAs, InAs, and InSb .2. Ordering of the iodine overlayer
- 1996
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 54:3, s. 2114-2120
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Tidskriftsartikel (refereegranskat)abstract
- The overlayer formed by the reaction of molecular iodine (I-2) with GaAs(001), InAs(001), and InSb(001) is investigated with synchrotron soft x-ray photoelectron spectroscopy (SXPS) and scanning tunneling microscopy (STM). Two components, separated by about 0.5 eV, are present in all of the I 4d SXPS spectra. At very low iodine coverages, the high binding energy (BE) component dominates. When the iodine coverage saturates, however, the two components have equal intensities. In contrast to GaAs and InAs, exposure of InSb(001)-c(8x2) to additional I-2 results in a further increase of the relative intensity of the low-BE component. STM images of I-2 covered InSb(001)-c(8x2) directly reveal the ordering in the overlayer. Islands are visible for submonolayer coverages, suggesting that adsorption occurs via a mobile precursor state. STM images feature occupies a 1x1 unit cell with the same spacing as bulk-terminated InSb(001). The other feature has a coverage of similar to 1/3 ML and is arranged in pairs oriented along the [110] azimuth.
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| 9. |
- Simpson, W C, et al.
(författare)
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Role of surface stoichiometry in the Cl-2/GaAs(001) reaction
- 1996
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Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films. - : American Vacuum Society. - 0734-2101 .- 1520-8559. ; 14:3, s. 1815-1821
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Tidskriftsartikel (refereegranskat)abstract
- The room-temperature reaction of Cl-2 with GaAs(001)-4x6, -c(2x8), and -c(4x4) surfaces is studied with synchrotron soft x-ray photoelectron spectroscopy. The chemical composition of the reacted surfaces is found to depend on the stoichiometry of the starting surface. In all cases, the reaction occurs stepwise, with Ga and As monochlorides formed prior to the dichlorides. The Ga-rich surface is initially more reactive than either of the As-rich surfaces and it forms more GaCl than the As-rich surfaces, which instead form more AsCl. The sticking coefficient for chlorine on GaAs(001) decays exponentially with coverage. A contribution from Cl atoms comprising the surface dichlorides is identified in the Cl 2p core-level spectra. (C) 1996 American Vacuum Society.
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| 10. |
- Baudin, K, et al.
(författare)
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Sputtering of large size clusters from solids bombarded by high energy cluster ions and fullerenes
- 1996
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Ingår i: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS. - : ELSEVIER SCIENCE BV. - 0168-583X. ; 112:1-4, s. 59-63
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- It is shown that polyatomic ions at high energy (MeV) are able to emit large size cluster ions with a high yield when they bombard solid surfaces. Results on sputtering of clusters ejected from inorganic and organic targets as well as sputtering of C-n(-)
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