1. Graduate Institute of Electronics Engineering National Taiwan University Taipei 106 Taiwan
2. Center for Integrated Nanotechnologies Sandia National Laboratory, Albuquerque Albuquerque NM 87185 USA
3. Research Center for Applied Sciences Academia Sinica Taipei 115 Taiwan
4. Department of Electrical Engineering National Taiwan University Taipei 106 Taiwan
5. Taiwan Semiconductor Research Institute Hsinchu 300 Taiwan