2D Raman band splitting in graphene: Charge screening and lifting of the K-point Kohn anomaly.

ABSTRACT: Pristine graphene encapsulated in hexagonal boron nitride has transport properties rivalling suspended graphene, while being protected from contamination and mechanical damage. For high quality devices, it is important to avoid and monitor accidental doping and charge fluctuations. The 2D Raman double peak in intrinsic graphene can be used to optically determine charge density, with decreasing peak split corresponding to increasing charge density. We find strong correlations between the 2D ₁ and 2D ₂ split vs 2D line widths, intensities, and peak positions. Charge density fluctuations can be measured with orders of magnitude higher precision than previously accomplished using the G-band shift with charge. The two 2D intrinsic peaks can be associated with the "inner" a

SUBMITTER: Wang X 

PROVIDER: S-EPMC5648804 | biostudies-literature | 2017 Oct

REPOSITORIES: biostudies-literature