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O: Fachverband Oberflächenphysik

O 49: Poster: Nanostructures on Surfaces I

O 49.28: Poster

Dienstag, 13. März 2018, 18:15–20:30, Poster A

Field emission investigations on flat polycrystalline Cu and Nb samples after argon-ion bombardment and pulsed laser treatment — •Süleyman Soykarci, Hendrik Bürger, Vitali Porshyn, Pavel Serbun, Dirk Lützenkirchen-Hecht, and Günther Müller — Bergische Universität Wuppertal, Gaußstr. 20, 42119 Wuppertal

In the present work, systematic investigations of polycrystalline Cu and Nb surfaces before and after Ar+ irradiation at 5 keV as well as laser treatments at different energies (300 uJ-2000 uJ) with a varying number of pulses (20-200) were performed by means of optical profilometry, atomic force microscopy and high-resolution scanning electron microscopy. In addition, local FE measurements were performed using a tungsten truncated cone needle anode in a field emission scanning microscope [1]. The results of ion bombardment indicated that the first detectable changes of the Cu and Nb surfaces occurred already after 3 min of ion bombardment. A reduction of the β-factors of sharp emitters was observed, resulting in an increase of the onset field values. The measurements on laser treated Nb samples showed an increase of the initial surface roughness values, however local field emission measurements (Øa= 30 um, z = 11 um) showed that the onset field for FE shifted to E > 700 MV/m. Detailed results will be presented and discussed at the conference. The work is funded by BMBF project 05H2015. [1] D. Lysenkov and G. Müller, Int. J. Nanotechnology 2, 239 (2005).