1. Center of Semiconductor Technologies and LasersInstitute of Physics of NAS of Belarus 68 Nezalezhnasci Avenue Minsk 220072 Belarus
2. Tyndall National InstituteUniversity College Cork Lee Maltings, Dyke Parade Cork T12R5CP Ireland
3. SemiTEq JSC 27 Engels Ave Saint-Petersburg 194156 Russia
4. Centre of Nanoheterostructure PhysicsIoffe Institute 26 Polytekhnicheskaya Saint-Petersburg 194021 Russia