1. Department
of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
2. Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
3. Department
of Applied Physics, Aalto University, P.O. Box 11100, FI-00076 Aalto, Finland
4. Institute of Ion
Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01314 Dresden, Germany
5. Department of Electrical
and Computer Engineering, University of Nebraska—Lincoln, Lincoln, Nebraska 68588, United States