1. Division of Physics and Applied Physics, School of Physical
and Mathematical Sciences, Nanyang Technological University, Singapore 637371
2. NOVITAS, Nanoelectronics Center of Excellence,
School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798
3. Energy Research
Institute @ NTU (ERI@N), Nanyang Technological University, 50 Nanyang
Drive, Singapore 637553