Due to a Volmer-Weber growth mode, the deposition of ultrathin gold films on molybdenite substrates leads to the formation of three-dimensional gold islands. The light emission detected on these islands has been attributed to a radiative decay of localized plasmons excited by inelastic tunneling electrons. This emission exhibits puzzling properties compared to what is usually observed on thicker gold films. Spectral analysis of emitted light enables current-voltage characteristics of the ${\mathrm{A}\mathrm{u}/\mathrm{M}\mathrm{o}\mathrm{S}}_2$ interface to be determined at a nanometer scale.

• Received 6 February 2001

DOI:https://doi.org/10.1103/PhysRevB.66.045401