[1] Taras Shevchenko Natl Univ Kyiv, Volodymyrska Str 64, UA-01601 Kiev, Ukraine
[2] Georgia Inst Technol, Sch Mat Sci & Engn, Atlanta, GA 30332 USA
[3] Belgorod State Univ, Pobedy Str 85, Belgorod 308015, Russia
[4] Sevastopol State Univ, Dept Phys, UA-299053 Sevastopol, Ukraine
[5] Tech Univ Ilmenau, Inst Chem & Biotechnol, Weimarer Str 25, D-98693 Ilmenau, Germany