Epitaxial growth of Co3O4 on CoO(100)

被引:122
作者
Carson, GA
Nassir, MH
Langell, MA
机构
来源
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS | 1996年 / 14卷 / 03期
关键词
D O I
10.1116/1.580310
中图分类号
TB3 [工程材料学];
学科分类号
0805 ; 080502 ;
摘要
Under mildly oxidizing ultrahigh vacuum conditions, it is possible to form on top of CoO(100) single crystal substrates, thin films that have higher oxygen content but that preserve the overall symmetry of the CoO(100) low-energy electron diffraction pattern. X-ray photoelectron spectroscopy (XPS) and high-resolution electron-energy-loss spectroscopy (HREELS) data indicate that the epitaxial film grown on CoO(100) at 625 K and 5x10(-7) Torr is Co3O4-like in both oxygen content and XP/HREEL spectroscopic characteristics. Both materials are closest packed in lattice oxygen, with the mismatch of bulk O2--O2- distances of approximately 5%. However, the Co3O4 is only able to grow to a thickness of approximately 5 Angstrom before the oxidation process halts. It is proposed that the orientation of Co3O4 that forms most readily on the CoO(100) surface does not present a thermodynamically stable orientation of the bulk Co3O4 substrate but is that which grows under the constraint of the best CoO(100)/Co3O4 epitaxial arrangement. While the mismatch in lattice parameters may in part be to blame for the limitation of higher oxide thickness, thicker oxide films have been grown under conditions with significantly larger mismatch. (C) 1996 American Vacuum Society.
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页码:1637 / 1642
页数:6
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