Probing depth of soft x‐ray absorption spectroscopy measured in total‐electron‐yield mode

Abstract

Abstract Two series of experiments on well‐characterized systems were performed to examine the probing depth of soft x‐ray absorption spectroscopy (XAS) measured in total‐electron‐yield (TEY) mode. First we measured the Ni 2 p 3/2 absorption spectra of Ni(100) covered with Tb as a function of the overlayer thickness. Secondly we recorded the O 1s absorption spectra of Ta 2 O 5 films produced by controlled anodic oxidatio of Ta foils as a function of the oxide thickness. The mean probing depth (MPD) was found to be much shorter than previously assumed (for O 1s, only 1.9 nm). The relative importance of those cascade mechanisms that lead to the electron current measured in TEY is discussed.