1. Electrical Engineering and Computer Sciences, University of California at Berkeley, Berkeley, California 94720, United States
2. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
3. Department of Materials Science and Engineering, University of California at Berkeley, Berkeley, California 94720, United States
4. The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
5. School of Physics, University of Melbourne, Melbourne, VIC 3010, Australia
6. Department of Electrical and Electronic Engineering, University of Melbourne, Melbourne, Victoria 3010, Australia