Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 60: Poster Session IV (Solid/liquid interfaces; Semiconductors; Oxides and insulators; Graphene; Plasmonics and nanooptics; Electronic Structure; Surface chemical reactions; Heterogeneous catalysis)
O 60.15: Poster
Mittwoch, 16. März 2011, 17:30–21:00, P4
Surface photovoltage investigation of gold chains on Si(111) by two-photon photoemission — •Sebastian Otto, Kerstin Biedermann, and Thomas Fauster — Lehrstuhl für Festkörperphysik, Universität Erlangen-Nürnberg, Staudtstr. 7, D-91058 Erlangen, Germany
We present surface photovoltage measurements on Si(111)-(7×7) with monoatomic gold chains. The gold coverage was varied between zero and 0.6 ML, where the Si(111)-(5×2)-Au reconstruction covers the surface completely.
During the two-photon photoemission experiments the p- or n-doped samples were illuminated by infrared (IR, EIR=1.55 eV) and ultraviolet (UV, EUV=4.65 eV) laser pulses. For all coverages the photovoltage was determined for sample temperatures of 90 K and 300 K by variation of the IR and UV laser power.
P-doped as well as n-doped Si(111) wafers show a linear dependence of the photovoltage on gold coverage. This stands in contrast to scanning tunneling spectroscopy measurements [1], which show a coverage-independent photovoltage over a wide coverage range for n-doped wafers. While for p-doped wafers our experimentally determined photovoltage is in agreement with previous reports, for n-doped wafers the observed values are lower than expected.
[1] K. Sell et al., phys. stat. sol. (b) 1087, 247 (2010)