Strain Modulation of Graphene by Nanoscale Substrate Curvatures: A Molecular View

Abstract

Spatially nonuniform strain is important for engineering the pseudomagnetic field and band structure of graphene. Despite the wide interest in strain engineering, there is still a lack of control on device-compatible strain patterns due to the limited understanding of the structure-strain relationship. Here, we study the effect of substrate corrugation and curvature on the strain profiles of graphene via combined experimental and theoretical studies of a model system: graphene on closely packed SiO nanospheres with different diameters (20-200 nm). Experimentally, via quantitative Raman analysis, we observe partial adhesion and wrinkle features and find that smaller nanospheres induce larger tensile strain in graphene; theoretically, molecular dynamics simulations confirm the same microscopic structure and size dependence of strain and reveal that a larger strain is caused by a stronger, inhomogeneous interaction force between smaller nanospheres and graphene. This molecular-level understanding of the strain mechanism is important for strain engineering of graphene and other two-dimensional materials.

Strain Engineering of 2D Materials: Issues and Opportunities at the Interface

“…Due to the high flexibility of 2D materials and their vdW interaction to the substrate, out‐of‐plane deformed 2D materials can be directly achieved by transferring them onto patterned substrates ( Figure ) . This method has led to significant development of the design of substrate patterns, along with strategies to fully conform 2D materials to them .…”

On the propagation of Dirac fermions in graphene with strain-induced inhomogeneous Fermi velocity

“…The strain in graphene, as well as in the other two dimensional materials, can be achieved by putting the material on the substrate that is micro-structured [6] or mechanically deformed [7], [8]. The strain can also appear due to the mismatch of the lattices of the material and the substrate that gives rise to superlattices and associated Moire patterns [9].…”

Tunneling through Double Electrostatic Barriers in Strained Graphene

“…Another more important aspect is the recent proposal suggesting a realistic graphene quantum strain transistor (GQST) . The key characteristic of the proposed device is the high aspect ratio of the transistor channels ( and ), hence removing the need for ordered crystal edges, and independent control of both the mechanical strain in substrates and the charge density in the devices.…”