Molecular rectification in triangularly shaped graphene nanoribbons

We present a theoretical study of electron transport in tailored zigzag graphene nanoribbons (ZGNRs) with triangular structure using density functional theory together with the nonequilibrium Green's function formalism. We find significant rectification with a favorite electron transfer direction from the vertex to the right edge. The triangular ZGNR connecting to the electrode with one thiol group at each terminal shows an average rectification ratio of 8.4 over the bias range from −1.0 to 1.0 V. This asymmetric electron transport property originates from nearly zero band gap of triangular ZGNR under negative bias, whereas a band gap opens under positive bias. When the molecule is connected to the electrode by multithiol groups, the current is enhanced due to strong interfacial coupling; however, the rectification ratio decreases. The simulation results indicate that the unique electronic states of triangular ZGNR are responsible for rectification, rather than the asymmetric anchoring groups. © 2012 Wiley Periodicals, Inc.

[1]  Yuyuan Tian,et al.  Measurement of Single-Molecule Resistance by Repeated Formation of Molecular Junctions , 2003, Science.

[2]  M. Ezawa.  Graphene Nanoribbon and Graphene Nanodisk , 2007, 0709.2066.

[3]  R. Farghadan,et al.  A spin-filter device based on armchair graphene nanoribbons , 2011, 1101.2948.

[4]  Hua Zhang,et al.  Asymmetric electron transport realized by decoupling between molecule and electrode. , 2009, Physical chemistry chemical physics : PCCP.

[5]  M. Ratner,et al.  When things are not as they seem: quantum interference turns molecular electron transfer "rules" upside down. , 2008, Journal of the American Chemical Society.

[6]  Mathieu Kemp,et al.  Conductance of Molecular Wires: Influence of Molecule−Electrode Binding , 1999 .

[7]  P. Ordejón,et al.  Density-functional method for nonequilibrium electron transport , 2001, cond-mat/0110650.

[8]  D. Neuhauser,et al.  Quantum interference in polycyclic hydrocarbon molecular wires , 2004 .

[9]  Jian-wei Zhao,et al.  Electronic transportation through asymmetrically substituted oligo(phenylene ethynylene)s: studied by first principles nonequilibrium Green's function formalism. , 2006, The Journal of chemical physics.

[10]  Jian Wang,et al.  Ab initio modeling of quantum transport properties of molecular electronic devices , 2001 .

[11]  Zhenyu Li,et al.  Dithiocarbamate anchoring in molecular wire junctions: a first principles study. , 2006, The journal of physical chemistry. B.

[12]  A. Zunger,et al.  Self-interaction correction to density-functional approximations for many-electron systems , 1981 .

[13]  Jian-wei Zhao,et al.  Nonequilibrium Green's function study on the electronic structure and transportation behavior of the conjugated molecular junction: terminal connections and intramolecular connections. , 2009, The Journal of chemical physics.

[14]  Chen,et al.  Large On-Off Ratios and Negative Differential Resistance in a Molecular Electronic Device. , 1999, Science.

[15]  M. Reed,et al.  Conductance of a Molecular Junction , 1997 .

[16]  Zhenhua Zhang,et al.  The transport properties of D-σ-A molecules: A strikingly opposite directional rectification , 2011 .

[17]  M. Ratner,et al.  Electron Transport in Molecular Wire Junctions , 2003, Science.

[18]  Andre K. Geim,et al.  Electric Field Effect in Atomically Thin Carbon Films , 2004, Science.

[19]  Jinlong Yang,et al.  Will zigzag graphene nanoribbon turn to half metal under electric field , 2007, 0708.1213.

[20]  B. Alder,et al.  THE GROUND STATE OF THE ELECTRON GAS BY A STOCHASTIC METHOD , 2010 .

[21]  Weitao Yang,et al.  Quantum-interference-controlled molecular electronics. , 2008, Nano letters.

[22]  Jianwei Zhao,et al.  The diversity of electron-transport behaviors of molecular junctions: correlation with the electron-transport pathway. , 2010, Chemphyschem : a European journal of chemical physics and physical chemistry.

[23]  Jian-wei Zhao,et al.  Asymmetric electron transport through a conjugated–saturated hydrocarbon molecular wire , 2011 .

[24]  R. Baer,et al.  Phase coherent electronics: a molecular switch based on quantum interference. , 2002, Journal of the American Chemical Society.

[25]  M. Tsukada,et al.  A Novel Viewpoint for Source-drain Driven Current inside Triangular Nanographene : Close Relationship with Magnetic Current , 2004 .

[26]  Kurt Stokbro,et al.  Do Aviram-Ratner diodes rectify? , 2003, Journal of the American Chemical Society.

[27]  Meir,et al.  Landauer formula for the current through an interacting electron region. , 1992, Physical review letters.

[28]  Jian-wei Zhao,et al.  Molecular Rectification Based on Asymmetrical Molecule−Electrode Contact , 2010 .

[29]  Jian-wei Zhao,et al.  Theoretical Investigation on the Electron Transport Path through the Porphyrin Molecules and Chemisorption of CO , 2009 .

[30]  Yan Guo,et al.  Length-dependent conductance of molecular wires and contact resistance in metal-molecule-metal junctions. , 2008, Chemphyschem : a European journal of chemical physics and physical chemistry.

[31]  D. Sánchez-Portal,et al.  The SIESTA method for ab initio order-N materials simulation , 2001, cond-mat/0111138.

[32]  Ning Li,et al.  Theoretical investigation on the chemical sensing of metalloporphyrin-based molecular junction. , 2010, The Journal of chemical physics.

[33]  J. Cornil,et al.  A Theoretical Study of Substitution Effects in Unimolecular Rectifiers , 2008 .

[34]  M. Ezawa.  Metallic graphene nanodisks: Electronic and magnetic properties , 2007, 0707.0349.

[35]  L. Liu,et al.  Fabrication of Graphene Nanodisk Arrays Using Nanosphere Lithography , 2008 .

[36]  R. Landauer,et al.  Generalized many-channel conductance formula with application to small rings. , 1985, Physical review. B, Condensed matter.

[37]  Hao‐Li Zhang,et al.  Theoretical investigation on molecular rectification on the basis of asymmetric substitution and proton transfer reaction. , 2008, The Journal of chemical physics.