1. School of Materials Science and Engineering, The University of New South Wales (UNSW) Sydney, Sydney, New South Wales 2052, Australia
2. Department of Physics, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, India
3. Electron Microscope Unit, UNSW Sydney, Sydney, New South Wales 2052, Australia
4. ARC Centre of Excellence in Future Low-Energy Electronics Technologies, UNSW Sydney, Sydney, New South Wales 2052, Australia
5. School of Chemical and Biomolecular Engineering, University of Sydney, Sydney, New South Wales 2006, Australia
6. School of Chemical Engineering, UNSW Sydney, Sydney, New South Wales 2052, Australia
7. College of Science and Engineering, Flinders University, Bedford Park, South Australia 5042, Australia
8. Flinders Institute for Nanoscale Science and Technology, Flinders University, Adelaide, South Australia 5042, Australia