1. Okanagan MicroElectronics and Gigahertz Applications (OMEGA) Laboratory, School of Engineering, University of British Columbia, Kelowna V1V 1V7, Canada
2. Central European Institute of Technology, Brno University of Technology, Purkynova 123, Brno 61200, Czech Republic
3. Center of Materials and Nanotechnology, Faculty of Chemical Technology, University of Pardubice, Nam. Cs. Legii 565, 53002 Pardubice, Czech Republic