1. Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
2. Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
3. Department of Electrical Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
4. SPM Labs LLC, Tempe, AZ 85283, USA.
5. Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
6. Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
7. Biointerfaces Institute, University of Michigan, Ann Arbor, MI 48109, USA.