1. Department of Electrical and Computer Engineering, The University of Texas at El Paso, El Paso, Texas 79968, USA
2. Metallurgical, Materials and Biomedical Engineering, The University of Texas at El Paso, El Paso, Texas 79968, USA
3. Department of Chemistry, The University of Texas at El Paso, El Paso, Texas 79968, USA
4. Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
5. Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA