Determination of edge purity in bilayer graphene using μ-Raman spectroscopy

Abstract

Polarization resolved µ-Raman spectroscopy was carried out at the edges of bilayer graphene. We find strong dependence of the intensity of the G band on the incident laser polarization, with its intensity dependence being 90 • out of phase for the armchair and zigzag case, in accordance with theoretical predictions. For the case of mixed-state edges we demonstrate that the polarization contrast reflects the fractional composition of armchair and zigzag edges, providing a monitor of edge purity, which is an important parameter for the development of efficient nanoelectronic devices.

Quantum inductance and high frequency oscillators in graphene nanoribbons

“…Figure 2a shows the total capacitance as a function of several typical dielectric materials. The quantum capacitance of a 2.5 nm GNR is shown in Fig 2b. While optical properties and carrier transport in GNR's are in general affected by the particular graphene edge state such as armchair, zigzag, or mixed edges [42], for simplicity we consider GNRs with pure armchair boundaries [43].…”

Visualization of arrangements of carbon atoms in graphene layers by Raman mapping and atomic-resolution TEM

“…Several techniques, such as atomic force microscopy (AFM), scanning tunneling microscopy (STM), transmission electron microscopy (TEM) and Raman spectroscopy, have been used to study the edge/crystal orientations and the stacking orders of graphene18192021222324252627282930. Among them, Raman spectroscopy with Raman mapping is the most favored due to its high spectral efficiency (tens of milliseconds integration time for a clear spectrum), non-destructiveness and lack of special sample preparation.…”

Pseudospin for RamanDband in armchair graphene nanoribbons

“…Moreover, the on-site interaction induced by u q (x) is symmetric about two sublattices, while that induced by v q (x) is antisymmetric, as is evident from the matrices σ 0 and σ z in Eqs. (8) and (14). From Eq.…”

“…This polarization dependence of the D band has been confirmed in many experiments. [3][4][5][6] Several experimental groups have observed a correlation between the D and G bands, [7][8][9]13,19 suggesting that the G x Raman intensity is suppressed at the armchair edge. Another example is the correlation between the frequency hardening/softening behavior of the D band due to doping (Kohn anomaly effect) and that of the G y band.…”