1. Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
2. Department of Physics, Stanford University, Stanford, California 94305, United States
3. Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305, United States
4. Department of Applied Physics, Stanford University, Stanford, California 94305, United States
5. Department of Chemistry, University of California, Berkeley, California 94720, United States
6. Department of Materials Science and Engineering, University of California, Berkeley, California 94720, United States
7. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
8. Kavli Energy NanoScience Institute, Berkeley, California 94720, United States