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Abnormal electron emission from MgO thin film under ion irradiation

2005; Wiley; Volume: 37; Issue: 2 Linguagem: Inglês

10.1002/sia.1949

1096-9918

Takuji Tsujita, T. Nagatomi, Y. Takai,

Electronic and Structural Properties of Oxides

Abstract Energy distributions of secondary electrons from an MgO thin‐film surface under ion irradiation were investigated. The abnormal ion‐induced secondary electron emission was observed in addition to the normal emission. The abnormal emission observed in the present study is found to be a kind of self‐sustained emission because it continued after stopping ion irradiation. The energies of the abnormal secondary electrons are lower than the vacuum level at the MgO surface by ∼7–10 eV and its energy distribution is close to the profile of the density‐of‐states of the valence band of MgO. The results strongly suggested that the abnormal electron emission observed in the present study is due to field emission of the valence electrons of MgO through a mechanism other than the Malter effects or the Townsend Avalanche effect. Copyright © 2005 John Wiley & Sons, Ltd.