Published: August 01, 2017
Chiashain Chuang, Yanfei Yang, Sujitra J. Pookpanratana, Christina A. Hacker, Chi-Te Liang, Randolph E. Elmquist
Atmospheric chemical doping can be used to modify the electronic properties of graphene. Although extensive experimental work on tuning atmospheric chemical doping of graphene has been reported, such a study of graphene on SiC is still lacking. Here we report that the chemical doping (oxygen and water vapor) of low-carrier-density monolayer epitaxial graphene on SiC can be readily tuned by a simple low-temperature (T near 450 K), in-situ vacuum annealing method. Such an approach allows, for the first time, the observation of a crossover from disordered graphene (mu-sub-t/mu-sub-q ~2) to an ordinary metal (mu-sub-t/mu-sub-q ~1) with decreasing carrier density where mu-sub-t and mu-sub-q are transport mobility and quantum mobility, respectively. In the low carrier density limit, our results are consistent with the theoretical prediction that mu-sub-t is inversely proportional to charged impurity density. Our data also suggests that atmospheric chemical doping can be used to vary intervalley scattering in graphene which plays a crucial role in backward scattering events.
Pub Type: Journals
carrier density, graphene, chemical doping, quantum mobility, electron scattering
Created August 01, 2017, Updated September 05, 2017