1. Department of Electronic Systems, Norwegian University of Science and Technology (NTNU), Trondheim NO-7491, Norway
2. Department of Engineering and Applied Sciences, Sophia University, Tokyo 102-8554, Japan
3. SINTEF Industry, Trondheim NO-7465, Norway
4. Department of Physics, Norwegian University of Science and Technology (NTNU), Trondheim NO-7491, Norway
5. Sophia Nanotechnology Research Center, Sophia University, Tokyo 102-8554, Japan