Time-resolved Auger spectroscopy on thin films with excitation by short electron pulses

Abstract

In recent years, a broad spectrum of time-resolving techniques for surface analysis has emerged. Often utilising a combination of optical and electron pulses, methods like time-resolved electron energy-loss spectroscopy can investigate samples in a broad energy range, while providing temporal resolution in the femtosecond regime. In this thesis, a new technique will be introduced, which will determine the Auger lifetime in solid samples on thin films via THz streaking. Previously, this technique was limited to gaseous samples. The experimental setup will utilise a photon-driven electron gun to generate 138 (+12/−38) fs electron pulses. The Auger electrons will be generated by the electron pulses on the backside of the anode, which serves as a sample holder. The energy modulation of the electron signal induced by the THz pulses, which are reflected at the sample surface, allows to determine a phase shift between primary and Auger electrons and thus the decay time of the Auger process. With the newly developed methodology it was possible to determine the Auger lifetime of solid carbon to τ = 13 (+100/−13) fs.