Intramolecular photon emission from a single molecule in a scanning tunneling microscope

Abstract

A vibrationally resolved intramolecular photon emission from a single molecule was induced by tunneling electrons in a scanning tunneling microscope (STM). The resonant excitation of the emission was observed by tuning the bias voltage between the STM tip and the sample. The emission intensity of an individual vibronic peak goes through a maximum. The intrinsic linewidth ($\ensuremath{\sim}3.0\text{ }\text{meV}$, full width at half maximum) obtained from the emission spectra and the measured quantum yield ($\ensuremath{\le}1.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}\text{ }\text{photon}$ per tunneling electron) reveal the effects of different processes on the intramolecular photon emission. The comparisons between STM-induced photon emission and other techniques were made.