Triaxially strained suspended graphene for large-area pseudo-magnetic fields

Abstract

Strain-engineered graphene has garnered much attention recently owing to the possibilities of creating substantial energy gaps enabled by pseudo-magnetic fields (PMFs). While theoretical works proposed the possibility of creating large-area PMFs by straining monolayer graphene along three crystallographic directions, clear experimental demonstration of such promising devices remains elusive. Herein, we experimentally demonstrate a triaxially strained suspended graphene structure that has the potential to possess large-scale and quasi-uniform PMFs. Our structure employs uniquely designed metal electrodes that function both as stressors and metal contacts for current injection. Raman characterization and tight-binding simulations suggest the possibility of achieving PMFs over a micrometer-scale area. Current–voltage measurements confirm an efficient current injection into graphene, showing the potential of our devices for a new class of optoelectronic applications. We also theoretically propose a photonic crystal-based laser structure that obtains strongly localized optical fields overlapping with the spatial area under uniform PMFs, thus presenting a practical route toward the realization of graphene lasers.

Plasmon-Enhanced Raman Scattering by Multilayered Graphene at the Micro- and Nanoscale: SERS and TERS Analysis

“…As reported in ref , such a shift may indicate the occurrence of mechanical stress in the folded multilayered graphene film. The estimation made in accordance with ref gives a mechanical stress value of about 0.7%., which is in good agreement with the data reported refs and .…”

Dynamic tuning of WSe2 exciton emission via laser annealing

“…The bright spot at the gap center region of the dimer structure shows an average Raman 2D peak shift of nearly 40 cm -1 compared to the 2D peak of unstrained graphene. This indicates that the amount of tensile strain induced at the gap center is approximately 0.6% by comparing with other literature 7 . The simulation and experiment results agree well with each other.…”

Strong second-harmonic generation by sublattice polarization in non-uniformly strained monolayer graphene

“…However, a quantitative representation of sublattice polarization is currently still lacking. On the other hand, it is also well known that the localized strain can induce artificial gauge fields pseudo-magnetic fields (PMF) that can generate discrete pLLs 37,43,44 . Here, we develop a new theoretical framework that provides a relationship between non-uniform strain, sublattice polarization, and PMF (See Supplementary Note 3 for a detailed explanation of the theoretical framework).…”