Raman signature of defected twisted bilayer graphene

Layered two-dimensional crystal systems can exhibit complex interlayer interactions, which are influenced by local crystal structure and/or electronic variations. Here, we study the influence of defects in twisted bilayer graphene (TBG) using Raman spectroscopy. We explore the varied influence of defects on three characteristic Raman modes of both fully-defected TBG, with defects introduced in both layers, and half-defected TBG, with defects introduced in only a single layer. The resonance condition responsible for a strong enhancement of the G peak is sensitive to structural disorder and is quenched within a radius similar to 3 nm of defects, while the twist-angle dependence of the 2D peak is influenced only at the site of structural disorder (similar to 1 nm radius). (C) 2015 Elsevier Ltd. All rights reserved.