▎ 摘　　要

Contamination of graphene due to residues from nanofabrication often introduces background doping and reduces electron mobility. For samples of high electronic quality, post-lithography cleaning treatments are therefore needed. We report that mechanical cleaning based on contact mode atomic force microscopy removes residues and significantly improves the electronic properties. A mechanically cleaned dual-gated bilayer graphene transistor with hexagonal boron nitride dielectrics exhibited a mobility of similar to 36 000 cm(2)/Vs at low temperature. (C) 2012 American Institute of Physics. [doi:10.1063/1.3685504]