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Graphene Quantum Electromechanical Systems

Final Report Summary - GQEMS (Graphene Quantum Electromechanical Systems)

Graphene is the first truly two-dimensional material, consisting of a monoatomic membrane of a hexagonal carbon lattice. Thanks to its unique electronic and mechanical properties, it is widely considered as a new "wonder material" with a wide range of potential applications, which go from high frequency electronics to THz imaging and flexible sensors. The main objective of the project “Graphene quantum electromechanical systems” has been exploiting the unique coupling of electronic properties and mechanical degrees of freedom in graphene. In particular, we aimed at developing a new platform for mechanically-tunable quantum devices based on graphene, for exploring new regimes of quantum physics and for potential technological applications. We adopted an innovative and interdisciplinary approach grounded on both engineering-based microsystem-technology and low-temperature solid-state physics. In particular, we have been working on gaining control over the mechanical and electromechanical properties of suspended graphene nanostructures and membranes, in the low and high strain regime.
For this purpose, we made use of micro electromechanical systems (MEMS) and developed a new process technology to extend their regime of operation to low-temperatures, making them suitable for fundamental studies. By integrating graphene into low-temperature MEMS actuators, we realized a unique platform for the development of electromechanical systems with integrated graphene. Most remarkably, we showed how to induce well-controlled tunable strain fields and strain gradients in graphene, opening the way to the investigation of tunable pseudo-magnetic fields and their potential applications.
Moreover, we obtained a real breakthrough in understanding the role of local (nanometer-scale) strain variations as the ultimate limiting factor for the mobility of charge carriers in graphene. We also demonstrated that Raman spectroscopy is an efficient and non-invasive way of probing nanometer-scale strain variations, and therefore of assessing the structural and electronic quality of graphene. These two results have been instrumental for the development of a novel fabrication technology based on synthetic graphene that yields the largest high-mobility samples currently available worldwide and that is in principle scalable for industrial applications.