Dr. Michel Calame


High quality graphene for metrology


A particular case among two-dimensional materials, graphene offers extremely interesting physical properties for very diverse device applications. These include for instance electronic and optoelectronic transducers as well as free-standing membranes for filtering purposes or high-resolution soft matter imaging. Such developments however all face a central issue: the need for a scalable growth and transfer process leading to high-quality material showing good crystallinity and limited surface contamination.
A particularly challenging application is the realization of a graphene-based resistance standard for metrology using the Quantum Hall Effect (QHE). In collaboration with METAS (Federal Institute of Metrology, Switzerland), we have optimized a Chemical Vapour Deposition (CVD) process to grow high-quality single domain graphene that can be efficiently transferred to SiO2/Si substrates. Using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), electrical transport measurements, and quantum mechanical computer simulations, we identified the mechanisms to minimize the undesired p-doping effects resulting in par-ticular from H2O and O2 graphene contamination. We also achieved very low dissipation QHE in CVD graphene transferred onto SiO2/Si substrate and demonstrated high-precision Hall Effect quantization


Michel Calame is head of the laboratory for Transport at Nanoscale Interfaces at the Swiss Federal Laboratories for Materials Science & Technology (Empa) and Privat Docent at the De-partment of Physics, University of Basel. He received his PhD in condensed matter physics at the University of Neuchâtel (1998) and spent a postdoc in biophysics at the Rockefeller Univer-sity (NY, USA) before joining the University of Basel in 2000. In Basel, he was leading a research group on Nanoscale Hybrid Electronic Systems since 2011 and was staff member of the Swiss Nanoscience Institute (SNI), coordinating the SNI PhD program from 2013 until 2016. His research interests are on the fundamental electronic and opto-electronic transport properties of nanoscale devices and their application as bio-chemical sensors.