Femtosecond time-resolved core-level photoelectron spectroscopytracking surface photovoltage transients on

$\chem{{\it p}\tx{-}GaAs}$

Author： Siffalovic P. Drescher M. Heinzmann U.

E-ISSN： 1286-4854|60|6|924-930

ISSN： 0295-5075

Source： EPL (EUROPHYSICS LETTERS), Vol.60, Iss.6, 2010-03, pp. : 924-930

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Abstract

Visible-pump/extreme ultraviolet (EUV)-probe spectroscopy usingspectrally selected high harmonics of intense laser pulses isutilised for tracking the charge carrier dynamics onsemiconductor surfaces. The time evolution of the electric fieldin the surface layer of p-$\chem{GaAs(100)}$ is probed with70$\un{eV}$ femtosecond EUV pulses by measuring the kinetic-energyshifts of $\chem{Ga}$-3d core-level photoelectrons after excitationwith 3.1$\un{eV}$ femtosecond laser pulses. The observed transientchanges of the surface photovoltage reveal carrier transport fromthe bulk to the surface to occur within 500$\un{fs}$ afterphotoexcitation, while a subsequent relaxation is determined toevolve on a time scale of a few tens of picoseconds.