We have investigated charge transport in ZnTPPdT-Pyr molecular junctions using the lithographic MCBJ technique at room temperature and cryogenic temperature (6K). We combined low-bias statistical measurements with spectroscopy of the molecular levels using I(V) characteristics. This combination allows us to characterize the transport in a molecular junction in detail. This complex molecule can form different junction configurations, which is observed in trace histograms and in current-voltage (I(V)) measurements. Both methods show that multiple stable single-molecule junction configurations can be obtained by modulating the inter-electrode distance. In addition we demonstrate that different ZnTPPdT-Pyr junction configurations can lead to completely different spectroscopic features with the same conductance values. We show that statistical low-bias conductance measurements should be interpreted with care, and that the combination with I(V) spectroscopy represents an essential tool for a more detailed characterization of the charge transport in a single molecule.
@article{arxiv.1109.6434,
title = {Charge Transport in a Zn-Porphyrin single molecule junction},
author = {Mickael L. Perrin and Christian A. Martin and Ferry Prins and Ahson J. Shaikh and Rienk Eelkema and Jan H. van Esch and Jan M. van Ruitenbeek and Herre S. J. van der Zant and Diana Dulić},
journal= {arXiv preprint arXiv:1109.6434},
year = {2011}
}