1. Department
of Electronic Materials Engineering, Research School of Physics and
Engineering, The Australian National University, Canberra, Australian Capital
Territory 2601, Australia
2. St. Petersburg Academic University, Khlopina 8/3, 194021 St. Petersburg, Russia
3. Ioffe Physical Technical Institute of the Russian Academy of Sciences, Politekhnicheskaya 26, 194021 St. Petersburg, Russia
4. ITMO University, Kronverkskiy
pr. 49, 197101 St.
Petersburg, Russia
5. Australian National Fabrication
Facility, Research School of Physics and Engineering, The Australian National University, Canberra, Australian Capital Territory 2601, Australia