Dresden 2006 – scientific programme

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O: Oberflächenphysik

O 29: Poster session II (Nanostructures, Magnetism, Particles and clusters, Scanning probe techniques, Time-resolved spectroscopy, Structure and dynamics, Semiconductor surfaces and interfaces, Oxides and insulators, Solid-liquid interfaces)

O 29.38: Poster

Wednesday, March 29, 2006, 14:30–17:30, P2

Optimization of the preparation process for tips used in Scanning Tunneling Spectroscopy (STS) — •Stefan Ernst¹, Steffen Wirth¹, Michal Rams^1,2, and Frank Steglich¹ — ¹Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany — ²Institute of Physics, Jagiellonian University, 30-059 Kraków, Poland

Scanning Tunneling Spectroscopy (STS) is a powerful method to investigate the electronic structure of material surfaces. By means of STS, it is possible to probe the local density of states of a sample with sub-nanometre spatial resolution.

One prerequisite for high resolution and stability is a good tunneling tip. In our UHV STM systems, we plan on working predominantly with tips made of tungsten. A well-established way of producing tungsten tips is electrochemical etching. However, such tips are covered with a disturbing oxide layer and are usually not sufficiently sharp. Thus, facilities for further in-situ tip conditioning had to be added to our UHV-STM systems. The techniques for tip conditioning which have been investigated include direct annealing, electron beam heating and self-sputtering with light ions such as neon. Differently treated tips have been characterized by means of electron microscopy, field emission and STM experiments.