1. Department of Chemical and Biological Engineering William Mong Institute of Nano Science and Technology and Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction The Hong Kong University of Science and Technology Clear Water Bay Kowloon 999077 Hong Kong
2. Centre for Advanced 2D Materials Department of Physics National University of Singapore 117551 Singapore
3. School of Mathematical and Physical Sciences University of Technology Sydney Ultimo New South Wales 2007 Australia
4. Materials Characterization and Preparation Facility The Hong Kong University of Science and Technology Clear Water Bay Kowloon 999077 Hong Kong