In future microelectronic circuits a partial replacement of certain electronic functions by organic molecule junctions may become very likely. The realization of such concepts will benefit from a “monolithic” fabrication of nanoscale contacts on the same semiconductor wafer using current microelectronic process technology. We have investigated the fabrication of such nanogap electrode devices based on different layered semiconductor materials including Silicon-on-Insulator [1] and GaAs/AlGaAs heterostructures [2, 3].
In my presentation, I will focus on vertical nanogap electrode devices that comprise smooth metallic contact pairs situated at the sidewalls of pillar-like structures, with separations down to few nanometers. We have used these devices to study the electronic transport properties of 9-12 nm long, dithiolated oligo-phenylene-vinylene (OPV) “molecular wires” assembled onto the electrode gap from solution. A pronounced, non-linear current-voltage characteristic with a conductance gap of up to approx. ±1.5 V at low temperatures is observed. The magnitude of this gap can be correlated with the molecular structure at the termini of the molecules, in good agreement to model calculations [4].
References:
[1] S. Strobel, R. M. Hernández, A. G. Hansen, M. Tornow, J. Phys. Cond. Matt. (JPCM) 20, 374126 (2008)
[2] S. M. Luber, F. Zhang, S. Lingitz, A. G. Hansen, F. Scheliga, E. Thorn-Csányi, M. Bichler, M.Tornow, Small 3, 285 (2007)
[3] S. Strobel, S. Harrer, G. Penso Blanco, G. Scarpa, G. Abstreiter, P. Lugli, M. Tornow, Small 5, 579 (2009)
[4] R. Søndergaard, S. Strobel, E. Bundgaard, K. Norrman, A. G. Hansen, E. Albert, G. Csaba, P. Lugli, M. Tornow, F. C. Krebs, J. Mater. Chem. 19, 3899 (2009)
