Noise characterization of molecular junctions

Samples containing tunable cross-section gold nanojunctions were fabricated using advanced cleanroom technology. Low-frequency noise spectroscopy was applied to study peculiarities of the noise behavior of bare samples and those modified by organic molecules at low-voltage biases. Normalized noise power spectral density S
_I
/I
²
dependencies on the junction resistance (R) were analyzed. Before the break of the junction, noise power spectral density was found to scale proportionally to R
²
. It is shown that after modification of the sample by 1, 4-benzenedithiol (BDT) the noise level decreases in the ballistic regime of conductance. The results of this work are valuable for improving basic knowledge about nanoscale conductors as well as for the development of molecular electronics.