Femtosecond and Attosecond Electron Transfer Dynamics of Semiconductors Probed by the Core-Hole Clock Spectroscopy

Abstract

Ultrafast electron transfer dynamics is a relevant topic to fundamental as well as many applied areas like femtochemistry, heterogeneous catalysis, surface photochemistry, molecular electronics, solar energy, among others. One way to probe it is through the resonant Auger spectroscopy (RAS), which provides a synchrotron radiation-based alternative to time-resolved optical spectroscopies in studying charge dynamics in the femtosecond and attosecond time regimes. RAS following core excitation presents major advantages: (i) the core-hole lifetime probed by core level spectroscopy can be used as a fast internal clock and insofar very low time scales in the range of femtoseconds (10−15 s) down to hundred attoseconds (10−18 s) can be achieved, the so-called core-hole clock (CHC) method; (ii) the inherent atomic specificity of core levels; and (iii) the surface sensitivity of low energy electrons adds further up. Here, the CHC approach will be presented and as an illustration of its use CHC results for a polymeric thin film will be discussed and compared with already existing data.