[1] ETH, Dept Mat, Lab Multifunct Mat, Vladimir Prelog Weg 5, CH-8093 Zurich, Switzerland
[2] ETH, Dept Mat, Lab Mesoscop Syst, Honggerbergring 64, CH-8093 Zurich, Switzerland
[3] ETH, Dept Mat, Lab Electrochem Mat, Honggerbergring 64, CH-8093 Zurich, Switzerland
[4] Paul Scherrer Inst, Lab Micro & Nanotechnol, CH-5232 Villigen, Switzerland
[5] Paul Scherrer Inst, Swiss Light Source, CH-5232 Villigen, Switzerland