Dresden 2009 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 40: Methods: Scanning probe techniques I

O 40.8: Vortrag

Mittwoch, 25. März 2009, 16:45–17:00, SCH A316

Cross-sectional Scanning Tunneling Microscopy across a Metal-Semiconductor Interface - Structural and Electronic Properties on the Atomic Scale — Lars Winking, Martin Wenderoth, •Tim Iffländer, Thomas Druga, and Rainer G. Ulbrich — IV. Physikalisches Institut, Georg-August-Universität Göttingen

Understanding the formation of Schottky barriers has been a major theme of surface science for more than half a century. However, the various mechanisms that determine the barrier height are still subject to discussion. To a large part this is due to the lack of appropriate experimental techniques with atomic resolution and the difficulties associated with preparing well-defined epitaxial interfaces.

We report scanning tunnelling spectroscopy (STS) across a cleaved epitaxial GaAs(110)/Fe interface. It provides information on the structural as well as the electronic properties of the heterointerface on the atomic scale. Furthermore, in combination with 3D simulations of the tip induced band bending we are able to quantify both the local Schottky barrier height and the influence of single dopant atoms on the electrostatic potential landscape representing the space charge layer in the semiconductor. Our experimental data are discussed in the context of existing theoretical models for Schottky barrier formation, like the advanced unified defect model or the metal-induced gap states model.

This work was supported by the SFB 602 TP A7.