Journal Article

FZJ-2015-04412

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Quantitative description of photoexcited scanning tunneling spectroscopy and its application to the GaAs(110) surface

Schnedler, M.FZJ* ; Portz, V.FZJ* ; Weidlich, P. ; Dunin-Borkowski, R.FZJ* ; Ebert, P. (Corresponding Author)FZJ*

2015
APS College Park, Md.

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Please use a persistent id in citations: http://hdl.handle.net/2128/8885  doi:10.1103/PhysRevB.91.235305

Abstract: A quantitative description of photoexcited scanning tunneling spectra is developed and applied to photoexcited spectra measured on p-doped nonpolar GaAs(110) surfaces. Under illumination, the experimental spectra exhibit an increase of the tunnel current at negative sample voltages only. In order to analyze the experimental data quantitatively, the potential and charge-carrier distributions of the photoexcited tip-vacuum-semiconductor system are calculated by solving the Poisson as well as the hole and electron continuity equations by a finite-difference algorithm. On this basis, the different contributions to the tunnel current are calculated using an extension of the model of Feenstra and Stroscio to include the light-excited carrier concentrations. The best fit of the calculated tunnel currents to the experimental data is obtained for a tip-induced band bending, which is limited by the partial occupation of the C3 surface state by light-excited electrons. The tunnel current at negative voltages is then composed of a valence band contribution and a photoinduced tunnel current of excited electrons in the conduction band. The quantitative description of the tunnel current developed here is generally applicable and provides a solid foundation for the quantitative interpretation of photoexcited scanning tunneling spectroscopy.

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Contributing Institute(s):

1. Mikrostrukturforschung (PGI-5)

Research Program(s):

1. 141 - Controlling Electron Charge-Based Phenomena (POF3-141) (POF3-141)

Appears in the scientific report 2015

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Database coverage:
; ; ; Current Contents - Physical, Chemical and Earth Sciences ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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