Under-surface observation of thin-film alumina on NiAl(100) with scanning tunneling microscopy

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• 作者：C.T. Wang ; C.W. Lin ; C.L. Hsia ; B.W. Chang ; M.F. Luo ; ^{mfl28@phy.ncu.edu.tw}
• 关键词：Scanning tunneling microscopy ; Alumina ; NiAl ; Thin films ; Under-surface ; Density functional calculations
• 刊名：Thin Solid Films
• 出版年：2012
• 期刊代码：78_00406090
• 类别：ph
• 出版时间：30 March, 2012
• 卷：520
• 期：11
• 页码：3952-3959
• 文件大小：2746 K

摘要

Scanning tunneling microscopy (STM) was used to investigate the oxide structures underlying the surface of alumina thin-film grown on NiAl(100). At a bias voltage (on the sample) below 2.0 V, STM topography images of the alumina layer beneath the surface were obtained. A probe with depth of 2-8 脜 was readily attained. The under-surface observation shows that the film consists of stacked layers of alumina whereas the layered alumina unnecessarily comprises entire 胃-Al₂O₃ unit cells. The lattice orientation of the upper alumina layer differs from that of the lower one by 90掳 鈥?the newly grown oxide structurally matching the horizontal oxide rather than the lower oxide. The results indicate a growth process competing with the typical mode of epitaxial growth for the growth of alumina film.