Theory and Fundamentals

Micro and nano-mechanical components at the first glance seem to obey classical mechanics. However, many phenomena and properties in these devices are still fundamentally unclear. Two dimensional materials, for instance, can show intrinsic tensions, which could be related to manufacturing effects, but might also have a fundamental origin like Brownian fluctuations or van der Waals forces at the clamping point. Moreover, understanding the non-linearities at the nano scale is still elusive. For instance, damping of nano-membranes is high, non-linear and strongly temperature dependent for unknown reasons. Therefore, in this research theme we focus on the fundamentals and physics of micro and nano-mechanical systems (such as cantilevers, beams, and membranes) and their non-linear dynamics behaviour.

Design and Fabrication

Fabrication methods are key prerequisites for the study of the dynamics of micro and nanosystems. Although quite some work on archetypical devices like graphene drums has been performed, the fabrication and characterization of mechanical devices from 2D materials is still in its infancy. Current device fabrication methods have low yield, show large device-to-device variations and are not compatible with high-volume manufacturing. We intend to improve these methods, both by internal device fabrication and by collaborations with leading groups and companies. The facilities at TU Delft are excellent to achieve this goal, since nano and microstructures, with proper electrode configurations, can be created in the Kavli Nanolab and the Else Kooi Lab. We have collaborations with the companies Graphenea and Applied Nanolayers that transfer their CVD graphene layers on our structures.

Experimental Characterization

Experimental characterization of nanoscale devices is an important challenge. Since device dimensions are smaller than the optical wavelength, optical methods have their limitation. On the other hand, measurements by scanning probe techniques like AFM have the drawback of strong tip-device interactions that modify device properties and are not able to capture the dynamics of these devices at high frequencies. Therefore, the investigation of novel actuation and detection methods for MEMS and NEMS will be a key aspect of this research line.

 

Furthermore, for designing and developing the ultimate NEMS devices, reliable and efficient descriptions of their dynamic response are essential. Therefore, another mission of the group is the theoretical characterization and development of accurate numerical tools that can be used in design of NEMS devices.

Applications

The research results of the other three research lines will position the group perfectly to study and develop new devices that can serve as prototypes for applications. As a consequence of their small mass and high flexibility, resonating cantilevers and nano membranes are extremely sensitive to external forces. For this reason it is the plan to study their use as mass sensors, stiffness sensors, pressure sensors, and gas sensors.