Affiliation: | aInstitute of Semiconductor Technology, Technical University Braunschweig, Hans-Sommer-Str. 66, 38106 Braunschweig, Germany;bII. Institute of Physics, Georg-August-University Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany;cPhysikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany;dDepartment of Semiconductor Physics, University of Ulm, Albert-Einstein-Allee 45, 89081 Ulm, Germany |