Nanotechnology

Prof. Andreas Stemmer

Mission

We target manufacturing techniques for the micro and nano-scale that rely on assembly principles observed in living cells. We particularly focus on maskless techniques outside of cleanrooms, at the solid-liquid interface, and suitable for a wide range of materials. Furthermore we focus on techniques to image nanostructures and to interface such structures to the macro world for signal and energy transmission.

Teaching focuses onto the fundamentals of the nanometer-scale engineering sciences. To this end, we elaborate common themes underlying and unifying key processes common in different disciplines ranging from physics and chemistry to biology and surface science. Students learn how to extract such basic principles from current literature and how to translate them into new and feasible technologies.

Highlights of research (2004)

Scanning probe microscopy has become an indispensable tool to investigate surfaces at the nanometer scale. We have developed Kelvin probe force microscopy from a purely qualitative electric imaging mode to a much more quantitative one through a combination of careful theoretical analysis and modelling, experimental validation, and clever instrumentation. This technique now allows for quantitative nanometer scale mapping of surface and imprinted potentials of active semiconductor devices and charge-storing materials. The same technique also allows for generating qualitative chemical and materials composition maps of technical and biological surfaces.

The technology behind the Kelvin probe force microscope was at the heart of the sensor-guided nanorobot we introduced in 1998, a modified atomic force microscope capable of following user-defined structures over long distances and analysing them on the nanometer scale. To this end, the sensor-guided nanorobot intelligently combined a priori knowledge of the user, low-resolution information from a camera overlooking the sample and multi-channel, nanometer scale information (e.g. topography, electric potential, friction) acquired with a single microfabricated probe.

Although our sensor-guided nanorobot reduced the time required for data acquisition by focusing solely onto the structures of interest rather than scanning an entire image, the actual scanning speed of the atomic force microscope remained slow. By applying modern approaches of control theory we recently succeeded in increasing the scanning speed of atomic force microscopes dramatically.