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DS: Fachverband Dünne Schichten
DS 20: Application of Thin Films
DS 20.5: Vortrag
Dienstag, 15. März 2011, 11:15–11:30, GER 38
Nanoscaled photoelectron ionisation detector based on lanthanum hexaboride — •Cordula M. Zimmer1, Jürgen Schubert2, Ulrich Kunze1, and Theodor Doll3 — 1Werkstoffe u. Nanoelektronik, Ruhr-Universität Bochum, Germany — 2Institute of Bio- and Nanosystems (IBN-1), Forschungszentrum Jülich, Germany — 3Institut für Physik, Johannes-Gutenberg Universität Mainz, Germany
In this work the development of a nanoscaled photo ionisation detector is presented, whose functionality is based on the photoelectric effect of lanthanum hexaboride (LaB6) thin films. Photoemitted electrons will be brought up to energies of 7 to 18 eV within a nano-electrode arrangement, which does not exceed the mean free path of molecules at 105 Pa (70 to 110 nm). This enables the ionising and sensing of specific gases such as hydrocarbons, solvents, organic and inorganic substances under ambient conditions without the risk of molecule fragmentation. The yield of photoelectron current emitted under ultraviolet (UV) irradiation was optimised by tuning the work function of the LaB6 films. The proper choice of the substrate material and/or the deposition of additional interlayers is important to establish a favourable crystal orientation and stoichiometry of the LaB6 film which lowers its work function.