@article {doi:10.1021/nn202463g,
	title = {Opening an Electrical Band Gap of Bilayer Graphene with Molecular Doping},
	journal = {ACS Nano},
	volume = {5},
	number = {9},
	year = {2011},
	note = {n/a},
	pages = {7517-7524},
	abstract = {<p>The opening of an electrical band gap in graphene is crucial for its application for logic circuits. Recent studies have shown that an energy gap in Bernal-stacked bilayer graphene can be generated by applying an electric displacement field. Molecular doping has also been proposed to open the electrical gap of bilayer graphene by breaking either in-plane symmetry or inversion symmetry; however, no direct observation of an electrical gap has been reported. Here we discover that the organic molecule triazine is able to form a uniform thin coating on the top surface of a bilayer graphene, which efficiently blocks the accessible doping sites and prevents ambient p-doping on the top layer. The charge distribution asymmetry between the top and bottom layers can then be enhanced simply by increasing the p-doping from oxygen/moisture to the bottom layer. The on/off current ratio for a bottom-gated bilayer transistor operated in ambient condition is improved by at least 1 order of magnitude. The estimated electrical band gap is up to \~{}111 meV at room temperature. The observed electrical band gap dependence on the hole-carrier density increase agrees well with the recent density-functional theory calculations. This research provides a simple method to obtain a graphene bilayer transistor with a moderate on/off current ratio, which can be stably operated in air without the need to use an additional top gate.</p>
},
	doi = {10.1021/nn202463g},
	url = {http://pubs.acs.org/doi/abs/10.1021/nn202463g},
	author = {Zhang, Wenjing and Lin, Cheng-Te and Liu, Keng-Ku and Tite, Teddy and Su, Ching-Yuan and Chung-Huai Chang and Lee, Yi-Hsien and Chu, Chih-Wei and Wei, Kung-Hwa and Jer-Lai Kuo and Lain-Jong Li}
}
