▎ 摘　　要

THz absorption and spectroscopic ellipsometry were used to investigate the charge dynamics and electronic structures of monolayer graphene with doping by triazine. The absorption spectrum of the triazine-doped film shows an optical excitation near 5.1 eV that is blue shifted compared with that of undoped analog. THz conductivity displays a coherent response of itinerant charge carriers at zero frequency and a disorder-induced finite frequency peak around 155 cm(-1). Drude plasma frequency (similar to 4400 cm(-1)) decreases with decreasing temperature while carrier relaxation time (similar to 13 fs) is almost temperature independent, implying the semiconducting behavior with thermal activation energy of 3 meV. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4752131]