1. Department of Electrical and Computer Engineering, and Center for Nanohybrid Functional Materials, University of Nebraska-Lincoln, Lincoln, NE 68588-0511, USA
2. Terahertz Materials Analysis Center, Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping SE-58183, Sweden
3. Semiconductor Materials Division, Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping SE-58183, Sweden
4. IPFN, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, 2695-066 Bobadela LRS, Portugal
5. Leibniz Institute for Polymer Research, Dresden, Germany