Mechanical strain and electric-field modulation of graphene transistors integrated on MEMS cantilevers

This work proposes a structure which allows characterization of graphene monolayers under
combined electric field and mechanical strain modulation. Our approach is based on a cantilever
integrated into a two-dimensional graphene-based field effect transistor (FET). This allows us
to change graphene properties either separately or together via two methods. The first way
involves electric field induced by the gate. The second is induction of mechanical strain caused
by external force pushing the cantilever up or down. We fabricated devices using
silicon-on-insulator wafer with practically zero value of residual stress and a high‑ quality
dielectric layer which allowed us to precisely characterize structures using both mentioned
stimuli. We used the electric field/strain interplay to control resistivity and position of the
charge neutrality point often described as the Dirac point of graphene. Furthermore, values of
cantilever to bend after the structure is released. Our device demonstrates a novel method of
tuning the physical properties of graphene in silicon and/or complementary
metal‑oxide‑semiconductor technology, and is thus promising for tunable physical or
chemical sensors.