Ion-induced electron emission from MgO by exciton decay into vacuum

SURFACE SCIENCE

卷:571

Article

Riccardi, P ; Ishimoto, M ; Barone, P ; Baragiola, RA

关键词: electron emission;    magnesium oxides;    ion-solid interactions;   

DOI  :  10.1016/j.susc.2004.07.031

来源: Elsevier

【 摘 要 】

We report observations of electron emission from MgO surfaces induced by impact of 100 eV-4 keV He+, Na+, Ne+, Ar+ ions. The energy distribution of emitted electrons is nearly independent of ion type and energy, showing that it is caused by the decay of an intrinsic electronic state of the solid excited by the ions. The similar yields and energy distributions for incident Na+ and Ne+ ions rule out the potential mechanism of electron emission. The results are consistent with a novel model in which excitation occurs when electrons centered at the oxygen anions are promoted during a collision with the projectile (kinetic mechanism), and transferred to a surface exciton that can autoionize since it lies above the vacuum level, as determined by combining measurements of electron energy loss and photoelectric threshold. (C) 2004 Elsevier B.V. All rights reserved.

【 授权许可】

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