▎ 摘　　要

We report a Raman spectroscopy study of graphene field-effect transistors with a controlled amount of defects introduced in graphene by exposure to electron-beam irradiation. Raman spectra are taken at T = 8 K over a range of back gate voltages (V-g) for various irradiation dosages (R-e). We study effects in the Raman spectra due to V-g-induced doping and artificially created disorder at various R-e. With moderate disorder (irradiation), the Raman G peak with respect to the graphene carrier density (n(FE)) exhibits a minimum in peak frequency and a maximum in peak width near the charge-neutral point (CNP). These trends are similar to those seen in previous works on pristine graphene and have been attributed to a reduction of electron-phonon coupling strength (D) and removal of the Kohn anomaly as the Fermi level moves away from the CNP. We also observe a maximum in I-2D/I-G and weak maximum in I-D/I-G near the CNP. All the observed dependences of Raman parameters on nFE weaken at stronger disorder (higher R-e), implying that disorder causes a reduction of D as well. Our findings are valuable for understanding Raman spectra and electron-phonon physics in doped and disordered graphene. (C) 2014 AIP Publishing LLC.