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- TORNEVIK, C, et al.
(författare)
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ADSORPTION OF SN ON SI(111)7X7 - RECONSTRUCTIONS IN THE MONOLAYER REGIME
- 1994
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Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 314:2, s. 179-187
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Tidskriftsartikel (refereegranskat)abstract
- Different monolayer phases of Sn on Si(111)7 x 7 have been studied by means of scanning tunneling microscopy (STM), core-level photoelectron spectroscopy (XPS), and Rutherford backscattering spectrometry (RBS). The STM results show that square-root 3 x square-root 3 reconstructions are obtained for room-temperature deposition of 1/3 ML of Sn followed by sample annealing in a broad temperature range. A T4 Sn adatom square-root 3 x square-root 3 phase is formed for temperatures between 500 and 800-degrees-C, with a concentration of defects that is strongly dependent on the temperature and which is as high as 25% for the lowest temperatures. Above 825-degrees-C a second square-root 3 x square-root 3 adatom reconstruction is formed, a mosaic-like phase with a 1: 1 mixture of Si and Sn atoms in T4 positions. The results from investigations of the higher coverage 2 square-root 3 x 2 square-root 3 reconstruction by XPS and RBS support the theory that this phase is a two-layer epitaxial Sn structure with all Si(111) dangling bonds saturated. The Sn coverage for this phase was determined to be between 1 and 1.2 ML.
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| 2. |
- GOTHELID, M, et al.
(författare)
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SN-INDUCED SURFACE RECONSTRUCTIONS ON THE GE(111) SURFACE STUDIED WITH SCANNING TUNNELING MICROSCOPY
- 1992
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Ingår i: Surface Science. - 0039-6028 .- 1879-2758. ; 271:3, s. L357-L361
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Tidskriftsartikel (refereegranskat)abstract
- Scanning tunneling microscopy (STM) has been used to study different Sn induced reconstructions on the Ge(111) surface; namely the (7 x 7), (5 x 5) and (square-root 3 x square-root 3)R30-degrees structures. The first two have been confirmed to be of the dimer adatom stacking fault (DAS) type with adatoms mainly being Sn. The (square-root 3 x square-root 3)R30-degrees superstructure was found at different Sn depositions. At 0.4 monolayer (ML) Sn coverage a homogeneous Sn adatom layer is adsorbed on the (1 x 1) surface in threefold sites directly over second-layer atoms (T4), while at low coverage, 0.1 ML, the top layer is a mixture of Sn and Ge atoms. We also propose the chemical identities of the different atoms seen in the STM images as related to their apparent height.
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