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 (∼4400 cm -1) decreases with decreasing temperature while carrier relaxation time (∼13 fs) is almost temperature independent, implying the semiconducting behavior with thermal activation energy of 3 meV.
Bibliographical noteFunding Information:
We acknowledge financial support from the National Science Council of Republic of China under Grant No. NSC98-2112-M-003-004-MY3.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)