1. School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
2. Research Techno Plaza, BorderX Block, Nanyang Technological University, 50 Nanyang Drive, 637553, Singapore
3. Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore