1. Division of Physics and Applied
Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371,
Singapore
2. School of Material
Science and
Engineering, Nanyang Technological University, Singapore 639798, Singapore
3. Division of Manufacturing Engineering,
School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798, Singapore
4. Department of Physics and Department
of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139,
United States
5. Division
of Microelectronics,
School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore