Strain engineering of graphene on rigid substrates

Graphene with a large tensile strain is a promising candidate for the new "straintronics'' applications. The current approaches of strain engineering on graphene are mainly realized by flexible or hollow substrates. In this work, a novel method for strained graphene on a rigid substrate assisted by PDMS stretching and interface adjustments is proposed. The Raman spectra show that the maximum strain of graphene on the SiO₂/Si substrate is ∼1.5%, and multiple characterizations demonstrate its high cleanness, flatness, integrity, and reliable electrical performance. The successful strain engineering is attributed to the protection of a layer of formvar resin and the interfacial capillary force of the buffering liquid. We believe this technique can advance strain-related fundamental studies and applications of two-dimensional materials.