Novel Technique for Inducing Large Area Uniaxial Strain in Graphene*

The effect of uniaxial strain on the electronic band structure of graphene is an exciting topic of inquiry, for both studies into the fundamental physics of 2D electron systems as well as applicative investigations in the design of “straintronics”. Tight binding calculations of the effect of strain in graphene have shown that strain on the order of 20 percent causes the Dirac points to merge, resulting in the formation of a band gap. However, experimental realization of this prediction has yet to be achieved, as current techniques for inducing strain in graphene cannot generate strain exceeding a few percent. We have devised a novel technique for inducing large uniaxial strain in graphene using a piezoelectric mechanism. The mechanism allows for controllable and continuously variable strain, with an expected upper limit on the inducible strain set only by the tearing of graphene at 26 percent. Device functionality and performance are discussed, and strained graphene samples are characterized by Raman spectroscopy. Results are compared with existing Raman spectra of strained graphene.