1. Department of Materials Science & Engineering; Drexel University; Philadelphia PA 19104 USA
2. A. J. Drexel Nanomaterials Institute; Drexel University; PA 19104 USA
3. Thin Film Physics Division; Department of Physics; Chemistry and Biology (IFM); Linköping University; SE-58183 Linköping Sweden
4. Materials Science and Technology Division; Oak Ridge National Laboratory; Oak Ridge TN 37381 USA