electromechanical properties; nanoelectronics; nanomechanics; nanofabrication; AFM; nanoribbons
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M M Benameur B. Radisavljevic J. S. Heron S. Sahoo H. Berger A. Kis (2011), Visibility of dichalcogenide nanolayers, in Nanotechnology
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Realization of nanoelectromechanical systems (NEMS) is the next step in the miniaturization of microelectromechanical systems (MEMS) that have become widely accepted as optical switches, accelerometers or actuators in ink jet printers. Due to their low mass, ultralow power consumption and high sensitivity, NEMS have promising applications as highly sensitive mass, displacement, charge and energy detectors.A typical NEMS device consists of a moving beam with dimensions in the nanometer range and an associated scheme for motion detection. Various nanoscale materials such as Si or Si3N4 nanowires, carbon or boron nitride nanotubes have been used in the past as mobile beams. The newest material with this role is graphene, which is especially interesting because it is only one atomic layer thick so it represents the ultimate limit in material thickness. Incorporating graphene into NEMS requires the development of appropriate motion detection schemes. In current graphene NEMS devices, the motion of the graphene membrane is detected optically. This approach is however not practical for real-world applications as it requires aligning expensive laser-based interferometers for every device. Direct, electrical read-out schemes are more promising in this respect.Graphene is also an interesting building block for nanoscale electronics but there are several major obstacles facing its widespread adoption. One of them is the fact that graphene does not have an energy gap.In this project we will address these two problems (motion detection and lack of band gap) by applying mechanical strain to graphene nanoribbons. We will measure nanoribbon conductance changes that result from mechanical stress which is also expected to induce a band gap that can be tuned by varying the magnitude of strain. We anticipate that other layered materials such as metal dichalcogenides will receive increasing attention in future. They offer some advantages compared to graphene and we will also study electromechanical response in nanoribbons fabricated using these materials.