[1] TU Wien, Inst Microelect, Vienna, Austria
[2] Ioffe Inst, St Petersburg, Russia
[3] Swiss Fed Inst Technol, Integrated Syst Lab, Zurich, Switzerland
[4] TU Wien, Inst Microelect, Christian Doppler Lab Single Defect Spect Semicon, Vienna, Austria
[5] TU Wien, Inst Photon, Vienna, Austria
[6] Natl Inst Mat Sci, Funct Mat Res Ctr, Res Ctr Funct Mat, Tsukuba, Ibaraki, Japan
[7] Natl Inst Mat Sci, Int Ctr Mat Nanoarchitecton, Tsukuba, Ibaraki, Japan
[8] King Abdullah Univ Sci & Technol KAUST, Phys Sci & Engn Div, Thuwal, Saudi Arabia