Devices are increasing in complexity, speed and performance, while reducing in size. Nano-electro-mechanical systems (NEMS) are devices that integrate electrical or mechanical functionality at the nanoscale. These systems have the potential to provide solutions to a range of technological problems in electronics and computing, and also have potential for use in sensing applications. Graphene and piezoelectric materials have great promise for use in NEMS devices but new preparation methods and measurement approaches are needed to determine material properties.
The EMRP project Metrology with/for NEMS (MetNEMS) investigated methods for characterising the electrical properties of NEMS devices and developed a new technique for manufacturing graphene to enable its use in these products.
- Developed techniques for growing and transferring graphene onto silicon support structures to form combined silicon and graphene NEMS.
- Established a non-contact method for the measurement of graphene resistance and used it to demonstrate that silicon and graphene NEMS are suitable for low frequency security surveillance and telecommunication applications.
- Developed near-field microwave systems to simultaneously excite and detect oscillations from a mechanical NEMS resonator. These signals form the basis for new calibration methods and transfer standards for characterising periodically moving samples.
- Developed a dynamic cooling technique using near-field microwave methods and graphene NEMS resonators and reduced the effects of thermal noise on NEMS device performance during force and mass measurements.
This project developed sensors based on NEMS technologies to provide traceable nanoscale measurements for the characterisation of material properties and other novel sensors at the micro or nanoscale. Industrial users are interested in using the projects non-contact measurement method for determining graphene sheet resistance which has potential for extension to other 2D material electrical properties.
The enhanced sensor capabilities developed in the project Metrology with/for NEMS will further advance NEMS-based sensor technology into areas such as security surveillance (through smaller and more sensitive sensors and detectors) and medical biosensors. In addition, NEMS sensors have potential for use in exciting new applications such as in ultra-sensitive biosensor detectors able to distinguish between different types of cancerous cells based on tumour mass. These developments have been made possible by the projects work on dynamic cooling to reduce the effects of thermal noise on NEMS.
The projects method for manufacturing graphene on a silicon substrate and electrical characterisation techniques for NEMS are essential steps towards new types of nano-technology devices and novel future NEMS applications.