1. CNRS, Bordeaux INP IMS UMR 5218 Univ. Bordeaux F33400 Talence France
2. UMI 3288 CINTRA CNRS‐NTU‐THALES Nanyang Technological University Research Techno Plaza 50 Nanyang Drive Singapore 637553 Singapore
3. Centre for Micro‐/Nano‐electronics School of Electrical and Electronic Engineering Nanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
4. School of Materials Science and Engineering Nanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore