The Eriksson Group in the Physics Department at the University of Wisconsin-Madison focuses on nanostructure fabrication and measurement, quantum computing, and semiconductor physics.
Our work on quantum computing is focused on silicon/silicon-germanium quantum dots. We fabricate these quantum dots in heterostructures grown by chemical vapor deposition. The quantum dot itself is defined by Schottky top gates, an approach that provides in-situ tunability of the device during measurement. Measurements are performed in a dilution refrigerator with a base temperature of 8 mK and a magnetic field of up to 14 T. We make use of precision electronics for ultra-low noise measurement of electronic properties.
We are also interested in the properties of thin membranes of silicon and silicon-germanium. In the form of free-standing nanomembranes, these materials enable the formation of strained silicon without the dislocations that typically arise during the formation of silicon-germanium buffer layers. In the form of ultra-thin silicon-on-insulator, membranes offer a platform to understand the interplay between surfaces and ultra-thin semiconductors.
Membranes and nanowires also provide a platform for the fabrication of thermoelectric devices with large surface to volume ratios and with internal interfaces between regions of different composition. Both of these features offer opportunities to enhance phonon scattering while maintaining good electrical properties, and thus may lead to enhanced thermoelectric properties.