Electronic transport, transition-voltage spectroscopy, and the Fano effect in single molecule junctions composed of a biphenyl molecule attached to metallic and semiconducting carbon nanotube electrodes

• Published in: Physical chemistry chemical physics : PCCP Vol. 16; no. 36; pp. 1962 - 1967
• Main Authors: Brito da Silva Júnior, Carlos Alberto, Pereira Leal, José Fernando, Pureza Aleixo, Vicente Ferrer, Pinheiro, Felipe A, Del Nero, Jordan
• Format: Journal Article
• Language: English
• Published: England 28.09.2014
• Subjects: Carbon nanotubes; Electric potential; Electronics; Lead (metal); Mathematical models; Semiconductors; Spectroscopy; Transport
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c4cp00016a

We have investigated electronic transport in a single-molecule junction composed of a biphenyl molecule attached to a p-doped semiconductor and metallic carbon nanotube leads. We find that the current-voltage characteristics are asymmetric as a result of the different electronic natures of the right and left leads, which are metallic and semiconducting, respectively. We provide an analysis of transition voltage spectroscopy in such a system by means of both Fowler-Nordheim and Lauritsen-Millikan plots; this analysis allows one to identify the positions of resonances and the regions where the negative differential conductance occurs. We show that transmittance curves are well described by the Fano lineshape, for both direct and reverse bias, demonstrating that the frontier molecular orbitals are effectively involved in the transport process. This result gives support to the interpretation of transition voltage spectroscopy based on the coherent transport model. We investigate electronic transport in semiconductor-molecule-metal junctions consisting of a biphenyl molecule attached to a p-doped semiconductor and metallic carbon nanotubes.