[1] Vilnius Univ, Fac Phys, Sauletekio 3, LT-10257 Vilnius, Lithuania
[2] Amplify My Probe Ltd, London NW1 1NJ, England
[3] Swiss Fed Inst Technol, Dept Chem & Appl Biosci, Vladimir Prelog Weg 1-5-10, CH-8093 Zurich, Switzerland
[4] Bielefeld Univ, Fac Chem, Univ Str 25, D-33615 Bielefeld, Germany
[5] Bielefeld Univ, Ctr Mol Mat CM2, Univ Str 25, D-33615 Bielefeld, Germany
[6] UCL, London Ctr Nanotechnol, London WC1H 0AH, England
[7] UCL, Dept Elect & Elect Engn, London WC1E 7JE, England