Spectroscopic characterization of <i>N </i>= 9 armchair graphene nanoribbons

Abstract

We investigate the N = 9 atoms wide armchair‐type graphene nanoribbons (9‐AGNRs) by performing a comprehensive spectroscopic and microscopic characterization of this novel material. In particular, we use X‐ray photoelectron, near edge X‐ray absorption fine structure, scanning tunneling, polarized Raman and angle‐resolved photoemission (ARPES) spectroscopies. The ARPES measurements are aided by calculations of the photoemission matrix elements which yield the position in k space having the strongest photoemission cross section. Comparison with well‐studied narrow N = 7 AGNRs shows that the effective electron mass in 9‐AGNRs is reduced by two times and the valence band maximum is shifted to lower binding energy by ∼0.6 eV. In polarized Raman measurements of the aligned 9‐AGNR, we reveal anisotropic signal depending upon the phonon symmetry. Our results indicate the 9‐AGNRs are a novel 1D semiconductor with a high potential in nanoelectronic applications.