1. Advanced Materials Department, Instituto Potosino de Investigación Científica y Tecnológica, camino a la presa San José 2055, Col. Lomas 4. Sección, 78216 San Luis Potosí, México
2. Microelectronics and Materials Physics Laboratories, Department of Electrical and Information Engineering, University of Oulu, P.O. Box 4500, FIN-90014 University of Oulu, Finland
3. Quantronics/Microtechnologies and Sensors, VTT Technical Research Centre of Finland, Espoo, P.O. Box 1000, TT3, 02044 VTT, Finland
4. Departamento de Ciencia e Ingeniería de Materiales e Ingeniería Química, Escuela Politécnica Superior, Universidad Carlos III de Madrid, Avenida Universidad 30, 28911 Leganés, Madrid, Spain
5. Department of Mechanical Engineering and Materials Science, Rice University, Houston, Texas 77005