Aachen PK 2003 – wissenschaftliches Programm

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K: Kurzzeitphysik

K 1: Short time-scale dynamics and diagnostics

K 1.2: Vortrag

Dienstag, 18. März 2003, 11:45–12:00, F04

Time-resolved PEEM of laser treated metal films — •Kai Kunze and Oleg Bostanjoglo — Optisches Institut P1-1, TU Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany

A pulsed photoemission electron microscope (PEEM) was used to image the laser treatment of metals. A time resolution of 5ns was realised by using a KrF excimer laser (248nm) as photon source. /par Metal surfaces were treated with a Nd:YAG pulse laser and the induced changes of work function were tracked on the time scale of nanoseconds to seconds. The laser energies were chosen such that the material was melted and surface layers removed. /par Experimental results of laser treatment of polycrystalline Aluminium, Chromium and Nickel films on quartz substrates are reported. The observed work function changes are explained by evaporation and redisposition of adsorbates, and by electron trapping by oxygen dissolved in the liquid metal.