Femtosecond time-resolved core-level photoelectron spectroscopy tracking surface photovoltage transients on
Fakultät für Physik, Universität
Bielefeld - Universitätsstr. 25 33615 Bielefeld, Germany
Accepted: 3 October 2002
Visible-pump/extreme ultraviolet (EUV)-probe spectroscopy using spectrally selected high harmonics of intense laser pulses is utilised for tracking the charge carrier dynamics on semiconductor surfaces. The time evolution of the electric field in the surface layer of p- is probed with 70 femtosecond EUV pulses by measuring the kinetic-energy shifts of -3d core-level photoelectrons after excitation with 3.1 femtosecond laser pulses. The observed transient changes of the surface photovoltage reveal carrier transport from the bulk to the surface to occur within 500 after photoexcitation, while a subsequent relaxation is determined to evolve on a time scale of a few tens of picoseconds.
PACS: 78.47.+p – Time-resolved optical spectroscopies and other ultrafast optical measurements in condensed matter / 72.40.+w – Photoconduction and photovoltaic effects / 73.20.-r – Electron states at surfaces and interfaces
© EDP Sciences, 2002