Dresden 2011 – scientific programme
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DS: Fachverband Dünne Schichten
DS 45: Ion Interactions with Nano Scale Materials I (Focused Session -- Organisers: Diesing, Facsko)
DS 45.3: Talk
Thursday, March 17, 2011, 11:45–12:00, GER 37
Internal Electron Emission detected in Metal-Insulator-Metal Thin Film Tunnel Devices bombarded with keV Cluster Projectiles — •Mario Marpe1, Christian Heuser1, Detlef Diesing2, and Andreas Wucher1 — 1Fakultät für Physik , Universität Duisburg-Essen, D-47048 Duisburg, Germany — 2Fakultät für Chemie, Universität Duisburg-Essen, D-45117 Essen, Germany
The electronic excitation of a solid surface bombarded by energetic ions manifests in the production of hot electrons, which can be either emitted from the surface ("kinetic electron emission") or remain within the solid. We use Metal-Insulator-Metal (MIM) tunneling junctions to detect and investigate hot charge carriers (electrons and holes) produced during bombardment of a metal surface with keV rare gas (Ar+) ions. The sample consists of a top metal film of about 20 nm thickness (the actual bombarded target surface), an underlying thin (2-3 nm) oxide film deposited and another metal electrode underneath. With such a device, excitations below the vacuum level can be detected as an internal electron emission current between the two metal electrodes. By combining the information obtained from external and internal emission, it is possible to gain information regarding the depth distribution of the generated excitation as well as the transport mechanism distributing the excitation away from its initial point of generation. We demonstrate this by varying the impact angle of the projectile ion beam. It is found that external and internal emission currents vary exactly in opposite direction when going from normal to oblique incidence.