Origin of noise in structures with tuned nanoconstrictions

Thin conducting gold films with nanoconstriction are characterized by noise spectroscopy with and without a single 1,4-benzenedithiol (BDT) molecule between the contacts. The low frequency noise spectral density demonstrates the 1/fa type behavior with a factor, a, near to 1. It is shown, that the normalized noise spectral density is proportional to the resistance R in power 3/2 for the case without a molecule as well as with a molecule. The experimental findings are in good agreement with theoretically predicted results. The results obtained are interpreted in terms of the fine tuning and evolution of structures with a nanoconstriction region. Structures with a single molecule demonstrate a lower noise level compared with the structures without it. Our results are promising for the development of nanostructures for future molecular electronics, functioning at room temperature.