Regensburg 2019 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 14: Poster
DS 14.13: Poster
Dienstag, 2. April 2019, 17:00–20:00, Poster E
Characterization of electron emission from diamond-coated tungsten tips — •Alexander Tafel1, Mingjian Wu2, Erdmann Spiecker2, Peter Hommelhoff1, and Jürgen Ristein1 — 1Department Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91058 Erlangen — 2Institute of Micro- and Nanostructure Research & Center for Nanoanalysis and Electron Microscopy (CENEM), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91058 Erlangen
Coating metal needle tips with diamond promises a robust high brightness photocathode useful for dielectric laser acceleration and time resolved electron microscopy and diffraction. The chemical and structural properties of tungsten tips coated with nanocrystalline diamond are thoroughly characterized. Electron diffraction and electron energy loss spectroscopy (EELS) confirm the presence of diamond with 20 nm sized columnar grains. Transmission electron microscopy and STEM-EELS reveal graphitic paths between diamond grains. The graphitic grain boundaries provide sufficient conductivity for the feedback of emitted electrons from the surface and - in case of surface hydrogen termination - the negative electron affinity of diamond substantially increases the electron yield. We present first experimental results of electron emission from diamond coated tips both in continuous field emission and femtosecond laser-triggered mode.