The study of shot noise for junctions formed by single molecules offers interesting new information that cannot be easily obtained by other means. At low bias it allows determining the transmission probability and the number of current carrying conductance channels[1, 2]

Shot noise is due to time-dependent fluctuations in the electrical current caused by the random transfer of discrete units of charge. To study shot noise, we measured the shot noise on single molecule Au-1,4-benzenedithiol (BDT)-Au junctions, fabricated with the mechanically controllable break junction (MCBJ) technique at 4.2K.

The figure is the results of shot noise as a function of the bias voltage appplied accross the Au-BDT-Au junctions from the noise spectrum between 1 and 100 kHz. The red line is the fit results, yielding τ1 = 0.23. For more precise research, we will measure shot noise on single molecule junctions using new measuring equipment with a high band gap between 1 and 1MHz.   

  1. D. Djukic and J. M. van Ruitenbeek, Nano Lett. 6, 789-793 (2006).
  2. A. Karimi, S. G. Bahoosh, M. Herz, R. Hayakawa, F. Pauly and E. Scheer, Nano Lett., 2016, 16 (3), 1803–1807

Information

Contributors: M. Prestel, M. Strohmeier
Former contributors: M. A. Karimi, Dongku Kim, D. Weber
External cooperations: T. Huhn, W. Belzig, F. Pauly
Fundings: SFB 767 project C2
Period: Jun 2017 - May 2018