1. School of Materials Science and Engineering; Nanyang Technological University; 50 Nanyang Avenue Singapore 639798 Singapore
2. NOVITAS; Nanoelectronics Centre of Excellence; School of Electrical and Electronic Engineering; Nanyang Technological University; Singapore 639798 Singapore
3. CNRS International NTU Thales Research Alliance (CINTRA); 50 Nanyang Drive Singapore 637553 Singapore
4. Division of Physics and Applied Physics; School of Physical and Mathematical Sciences; Nanyang Technological University; Singapore 637371 Singapore
5. Temasek Laboratories@NTU; Nanyang Technological University; Singapore 637553 Singapore