1. Department of Physics, University of Arizona, Tucson, Arizona 85721, USA
2. Department of Materials Science and Engineering, University of Wisconsin, Madison 53706, USA
3. Department of Electrical Engineering, University of California, Los Angeles, California 90095, USA
4. Science Department, Sunnyside High School, Tucson, Arizona 85706, USA
5. Inston, Inc., Los Angeles, California 90024, USA