tailieunhanh - First-principles Studies of CO2 and NH3 Gas Molecules Adsorbed on Graphene Nanoribbons
We present first-principles studies of CO2 and NH3 adsorbed on graphene nanoribbons (GNRs). The electronic and transport properties are calculated based on density functional theory combined with non-equilibrium Green's function method. Absorption energy, density of states, electron density deformation, charge transfer, current-voltage characteristics, and transmission spectra were analyzed. | VNU Journal of Science: Mathematics – Physics, Vol. 32, No. 2 (2016) 15-21 First-principles Studies of CO2 and NH3 Gas Molecules Adsorbed on Graphene Nanoribbons Nguyen Tien Cuong*, Nguyen Manh Tien Faculty of Physics, VNU University of Science, 334 Nguyen Trai, Thanh Xuan, Hanoi, Vietnam Received 20 March 2016 Revised 16 May 2016; Accepted 26 June 2016 Abstract: We present first-principles studies of CO2 and NH3 adsorbed on graphene nanoribbons (GNRs). The electronic and transport properties are calculated based on density functional theory combined with non-equilibrium Green's function method. Absorption energy, density of states, electron density deformation, charge transfer, current-voltage characteristics, and transmission spectra were analyzed. It is found that CO2 and NH3 adsorbed on GNRs exhibit acceptor-like and donor-like behaviors, respectively. Both CO2 and NH3 molecules show physissorption on GNRs with low adsorption energies and small charge transfers. In other words, the interactions between CO2 and NH3 molecules and GRNs are very weak. The results suggest that the sensitivity and selectivity of GRN-based gas sensors could be improved by introducing the dopant, defect, or modification of electronic structures of graphene. Keywords: First-principles, Graphene Nanoribbons, CO2 Adsorbed on Graphene, NH3 Adsorbed on Graphene. 1. Introduction∗ Graphene, the first truly 2D crystalline materials, has been attracting much attention since its successful fabrication in 2004 [1, 2]. It is a promising candidate for silicon replacement in semiconductor industry [3, 4] or gas sensing applications [5]. Graphene can be patterned into GNRs via lithographic [6, 7] or focus ion beam [8] techniques. GRNs have been investigated as alternative for gas sensors due to their high mobility, high surface area to volume ratio, easy micro fabrication, and controllable energy gap. The sensor properties are based on changes in resistivity due to molecules adsorbed on GRNs that
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