Photoelectron lifetime determination of Ag(1 1 1) films at the Fermi surface

The electronic properties of 10 monolayers Ag(1 1 1) films deposited onto Si(1 1 1)-7×7 substrates at room temperature have been studied by scanning the photoelectron intensity at the Fermi level in different symmetry directions. The main features observed in these profiles correspond to Lorentzian-like peaks produced by the pass of the sp band through the Fermi level. A simple model has been developed, which connects the photoemission peak linewidth with the lifetime of photoelectrons excited from the Fermi level. The obtained inverse photoelectron lifetime values have been found to be in excellent agreement with the typical values of the Ag single crystals. These results support the fact that the transport properties of well ordered Ag films grown onto silicon substrates are quite close to those expected in bulk-like silver crystals.