Angular resolved ups of surface states on GaAs(1̄1̄1̄) prepared by molecular beam epitaxy |
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Authors: | K. Jacobi C.v. Muschwitz W. Ranke |
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Affiliation: | Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faraday weg 4–6, D-1000 Berlin 33, Germany |
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Abstract: | The As-rich (2 × 2), a newly found (√3 × √3) and the (√19 × √19) surfaces of GaAs(1̄1̄1̄) are studied by angular resolved UPS (ARUPS). The (2 × 2) surface is prepared by molecular beam epitaxy and the others by mild annealing. For the (2 × 2) surface emission from surface states is observed, which shows dispersion periodic within the (2 × 2) surface Brillouin zone. Using s-polarized light and the known symmetry selection rules the uppermost surface bands between 1 and 2 eV below the valence band maximum are assigned to the As dangling bond orbital. The bands near 4 and 7 eV assigned to the backbonds. From the strong decrease of emission intensity of the As-derived surface states between the (2 × 2) and the annealed surfaces it is concluded that the character of the As dangling bond orbital must have been changed from sp3-hybridic to s-like. This gives further evidence for our recently proposed model for the (√19 × √19) surface, which is particularly applicable for the (√3 × √3) surface. |
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