1. Ernst Ruska‐Centre for Microscopy and Spectroscopy with Electrons Research Center Jülich 52425 Jülich Germany
2. School of Microelectronics Xi'an Jiaotong University Xi'an 710049 China
3. Institute of Physics University of Silesia Katowice 40007 Poland
4. Gemeinschaftslabor für Elektronenmikroskopie (GFE) RWTH Aachen Ahornstraße 55 52074 Aachen Germany