1. Départment de Chimie Physique Université de Genève 30, quai E. Ansermet CH 1211 Geneva 4 Switzerland
2. LumiNova AG Switzerland Speicherstrasse 60a CH-9053 Teufen Switzerland
3. Transport at Nanoscale Interfaces Laboratory Swiss Federal Laboratories for Materials Science and Technology Empa Dübendorf CH-8600 Switzerland
4. Advanced Technology Institute Department of Electrical and Electronic Engineering University of Surrey Guildford GU2 7XH UK
5. CNRS Univ. Bordeaux Bordeaux INP ICMCB UMR 5026 F-33600 Pessac France