Researchers at Columbia University in New York have made the first electrical-readout nanomechanical resonators made from graphene. The devices, which consist of vibrating sheets of graphene suspended over micron-sized trenches, could be used as highly sensitive, robust, mass detectors.
The researchers has made the graphene into a bridge-like resonators that vibrate at very high frequencies. The frequency changes each time a molecule is absorbed onto its surface.
The Columbia team made its devices by placing graphene sheets onto silicon/silica substrates, then patterning metal electrodes and etching away the silica to produce suspended graphene. The portion of each electrode that is in contact with the graphene is also suspended, which makes electrical readout easier later on.
The measurements show that the device is sensitive to around 1 zeptogram (10–21g), which is about two gold atoms at low temperatures...