Regensburg 2004 – scientific programme

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HL: Halbleiterphysik

HL 44: Poster II

HL 44.65: Poster

Thursday, March 11, 2004, 16:30–19:00, Poster A

Inhomogeneities in Au:GaAs(110) Schottky Barriers Studied with Cross-sectional Scanning Tunneling Spectroscopy — •M. Wenderoth, T.C.G. Reusch, and R. G. Ulbrich — IV. Physikalisches Institut, Universität Göttingen, D-37077 Göttingen

Inhomogeneities in Au:GaAs(110) Schottky barriers have been investigated with Cross-Sectional Scanning Tunnelling Spectroscopy. The influence of metal-induced gap states and the electrostatic potential of the depletion layer are visible in spatially resolved measurements. The electrostatic potential of the depletion layer shifts the current onsets in the tunneling spectra. By extracting the shift and from comparison with simulations, we are able to map variations in the local electrostatic potential in the depletion layer parallel and perpendicular to the interface on a near-atomic scale. This information is complementary to Ballistic Electron Emission Microscopy. The extracted SBH is in the range of 690 meV , which is somewhat smaller than the reported SBH of 950 meV for Au:GaAs(110) contacts prepared under similar conditions. The observed fluctuations of the potential at the interface of 2σ ≈ 60 meV are in good accordance with reported values of BEEM investigations.