Determination of the electron mean free path in the 1-1.8 eV energy range in thin gold layers using ballistic electron emission microscopy

Electron mean free path (lambda(a)) has been investigated using Ballistic E lectron Emission Microscopy (BEEM). Using the average collector current com puted from large scale BEEM images and a model in which the current exponen tially decreases in terms of metal thickness, a constant value of lambda(a) = 11 nm has been calculated in the 1-1.8 eV electron energy range. On smal l scale images, the study of well-defined BEEM domains shows that either la mbda(a) or the interface transmission factor (or both) may differ from thei r average values. These local variations from one grain to another are inte rpreted as interface defects and channeling of the electron beam due to the electronic and crystallographic of the gold layer.