1 School of Physics and Material Science, Anhui University, Hefei 230601, China;
2 College of Chemistry and Chemical Engineering, Anhui University, Hefei 230601, China;
3 National Laboratory of Infrared Physics, Shanghai Institute for Technical Physics, Chinese Academy of Sciences, Shanghai 230083, China
The inelastic electron tunneling spectroscopy (IETS) of four edge-modified finite-size grapheme nanoribbon (GNR)-based molecular devices has been studied by using the density functional theory and Green's function method. The effects of atomic structures and connection types on inelastic transport properties of the junctions have been studied. The IETS is sensitive to the electrode connection types and modification types. Comparing with the pure hydrogen edge passivation systems, we conclude that the IETS for the lower energy region increases obviously when using donor-acceptor functional groups as the edge modification types of the central scattering area. When using donor-acceptor as the electrode connection groups, the intensity of IETS increases several orders of magnitude than that of the pure ones. The effects of temperature on the inelastic electron tunneling spectroscopy also have been discussed. The IETS curves show significant fine structures at lower temperatures. With the increasing of temperature, peak broadening covers many fine structures of the IETS curves. The changes of IETS in the low-frequency region are caused by the introduction of the donor-acceptor groups and the population distribution of thermal particles. The effect of Fermi distribution on the tunneling current is persistent.
Received: 22 August 2016
Revised: 02 November 2016
Accepted manuscript online:
PACS:
31.15.es
(Applications of density-functional theory (e.g., to electronic structure and stability; defect formation; dielectric properties, susceptibilities; viscoelastic coefficients; Rydberg transition frequencies))
Project supported by the National Natural Science Foundation of China (Grant Nos.11304001, 51272001, 51472003, and 11174002), the National Key Basic Research Program of China (Grant No. 2013CB632705), the Ph. D. Programs Foundation for the Youth Scholars of Ministry of Education of China (Grant No. 20133401120002), the Foundation of State Key Laboratory for Modification of Chemical Fibers and Polymer Materials of Donghua University (Grant No. LK1217), the Foundation of Co-operative Innovation Research Center for Weak Signal-Detecting Materials and Devices Integration of Anhui University (Grant No. 01001795-201410), the Key Project of the Foundation of Anhui Educational Committee, China (Grant No. KJ2013A035), and the Ph. D. Programs Foundation of Anhui University, China (Grant No. 33190134).
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