1. Departamento de Física Universidade Federal do Paraná Caixa Postal 19044 Curitiba PR 81531‐990 Brazil
2. Center for Sensors and Devices Bruno Kessler Foundation (FBK) Trento 38123 Italy
3. School of Chemistry and Physics Queensland University of Technology (QUT) Brisbane QLD 4000 Australia
4. School of Electrical and Electronic Engineering Nanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
5. Centre for Materials Science Queensland University of Technology 2 George Street Brisbane QLD 4000 Australia
6. Centre for Biomedical Technologies Queensland University of Technology 2 George Street Brisbane QLD 4000 Australia