1. Fraunhofer Institute for Integrated Systems and Device Technology IISB, Schottkystr. 10, 91058 Erlangen, Germany
2. Chair of Electron Devices, University of Erlangen-Nürnberg, Cauerstr. 6, 91058 Erlangen, Germany
3. Department of Information Engineering, University of Padova, via Gradenigo 6/B, 35131 Padova, Italy
4. Naval Research Laboratory, 4555 Overlook Avenue, Washington, DC 20375, USA
5. EpiGaN, Kempische Steenweg 293, 3500 Hasselt, Belgium
6. CNRS-IEMN, Institute of Electronics, Microelectronics and Nanotechnology, Avenue Poincaré, 59650 Villeneuve d’Ascq, France