Nanoelectronics Piezoresistive strain sensors made of microcrystalline Silicon
The research activities in our group are divided between two main areas: thin film silicon devices and graphene devices. Within the first, we want to pursue the work on flexible piezoresistive strain sensors and solar cells; as for graphene we want to develop plasmonic devices that are excited using teraherz radiation and may form the basis of a new type of biosensors. We want to extend the research to other 2D materials, like hexagonal boron nitride (h-BN) and molybdenum di-sulfide and explore new routes that may open by combining them with graphene. We continue working on silicon nitride flexible multilayers for encapsulation of organic electronic devices. We will develop some workhorse devices that will be ready for integration in other platforms, like pin Si thin film photodetectors and zinc oxide TFTs.
We developed a technique using laser irradiation of 10 nm thick highly resistive amorphous silicon films containing B or P atoms that locally induces crystallization and dopant activation of the films allowing us to write patterns without resort to standard clean room photolithography, both on glass and polyimide substrates. A first batch of strain sensors manufactured on polyimide using laser-induced crystallization of Silicon was measured using a four-probe bending setup and showed a gauge factor of +5. The flexible sample already include six sensor orientations, and we plan to further develop this process so that more densely packed structures can be patterned by laser writing on doped a-Si:H.