From scanning tunneling spectroscopy measurements, we recently found evidence for the effect of electron-phonon interactions on the lifetime of hot electrons and holes. This information was obtained by measuring the linewidth of quantum well states resulting from the confinement of Shockley states in truncated hexagonal Ag nanopyramids. In the present paper, we show that a careful analysis allows us to obtain both the intrinsic and extrinsic broadening contributions. This latter contribution results from the lossy boundary scattering which is strongly reduced in this peculiar geometry. Indeed, we deduce the energy dependence of the reflection coefficient which remains higher, as usually observed in nanostructures like adatom islands and quantum corrals.

• Received 5 July 2011

DOI:https://doi.org/10.1103/PhysRevB.84.165420