1. Division of Solid-State Electronics, Ioffe Institute, 26 Politekhnicheskaya, St. Petersburg 194021, Russian Federation
2. Department of Physics and Technology of Nanostructures, Saint Petersburg Academic University, 8/3 Khlopin, St. Petersburg 194021, Russian Federation
3. CERN, CH-1211 Geneve 23, Switzerland
4. Centre of Technical Support “NAUKA,” 126 Prospect Mira, Moscow 129085, Russian Federation