Fabrication of Graphene-based Josephson junctions for Superconducting-to-Normal Switching Measurements
Abstract
We report on the fabrication of graphene-based Josephson junctions consisting of single layer graphene contacted by superconducting leads spaced 100-300 nm apart. The contacts are a Pd/Al bilayer, with the thin Pd layer providing high transparency contact to graphene and Al is the superconductor. The devices are fabricated using electron beam lithography and liftoff techniques. We also report on the progress of current-voltage measurements of these devices at temperatures as low as 20 mK. We specifically focus on the statistics of device switching from the superconducting state to the normal state. The use of graphene as a weak link allows novel control of the critical current by means of a gate voltage, and therefore we can tune the switching properties of these devices. Accumulated data provides insight into the study of the modified Josephson washboard potential [1] and studies of classical resonant activation and quantum energy level states of the associated phase particle trapped within a washboard potential well. Ongoing work studying these properties in devices with interdigitated shunting capacitors will also be presented. [4pt] [1] J. G. Lambert, et al., IEEE Trans. in Appl. Supercond. 21, 734 (2011).
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- February 2012
- Bibcode:
- 2012APS..MARL21008L