Transport phenomena in nanostructures
Magnetic multilayers are defined using molecular beam epitaxy (MBE) and structured using electron beam lithography (EBL). These devices which can have smallest structures of about 10 nm are electrically characterized. They are of central importance for the development of memory elements with a large density of structures on a chip. We investigate the switching behavior of nanoscopic magnets and the excitations, which accompany such mechanisms. Colloidal model systems help us in understanding magnetic interactions in general.
We develop techniques to electronically contact single organic molecules. Electrical current transport through single molecules has been actively investigated during the past years, because they promise new possibilities for scaling down sizes of electronic circuits. A technique for reliable fabrication of single molecule contacts, however, could not be demonstrated so far. Using EBL in combination with etching techniques we developed several such contacting techniques and use them for the electrical characterization for various molecules. Thus, we understand the electrical behavior of single molecular electronic building blocks and can use this knowledge for the development of real molecular electronic circuits. This topic is closely linked to the Research School NanoNet.
Nanomechanical resonators can be used for example as detectors or mechanical switches. Therefore these structures offer new possibilities in generating nanoscale electrical circuits as well. The damping behavior of such structures is not well understood. The goal of our experiments is therefore to use advanced structuring methods and modern materials to investigate the damping mechanisms in nanomechanical resonators.
The Nanofabrication Facility in Rossendorf (NanoFaRo) is serving a large number of internal and external users (currently around 40) running a vast variety of projects. We amassed extensive experience in high-resolution patterning (down to 6-7 nm) of the main semiconductor substrate materials such as silicon (Si) and silicon-on-insulator (SOI) for nanoelectronics and photonics applications as well as of a wide range of magnetic materials for spintronics, magnonics, etc. applications. Central to our activities is the high-precision contacting of nanostructures randomly distributed on a wafer surface such as bottom-up grown nanowires, DNA origami, flakes of 2D materials, etc.
We operate two EBL systems, Raith 150 Two and Raith e_LiNE plus (Raith GmbH), using different positive and negative resists.
For thin film deposition we use mainly two evaporation machines: UHV evaporation tool BETty (BESTEC GmbH) and LAB 500 evaporation tool (Leybold Optics GmbH), both equipped with electron beam and thermal evaporators, as well as a sputter system NORDIKO 2000 (NORDIKO Ltd.) equipped with 4 magnetrons: 2 operating in DC-mode and 2 operating in DC- or RF-mode.
More information here.