Stacking behavior of twin-free type-Boriented CeO2(111) films on hexagonal Pr2O3(0001)/Si(111) systems
Stacking behavior of twin-free type-Boriented CeO2(111) films on hexagonal Pr2O3(0001)/Si(111) systems
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DOI：
10.1103/physrevb.85.035302
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发表时间：
2012-01
影响因子：
3.7
通讯作者：
M. Zoellner;J. Dabrowski;P. Zaumseil;A. Giussani;M. Schubert;G. Lupina;H. Wilkens;J. Wollschläger;M. Reichling;M. Bäumer;T. Schroeder
中科院分区：
文献类型：
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作者：
M. Zoellner;J. Dabrowski;P. Zaumseil;A. Giussani;M. Schubert;G. Lupina;H. Wilkens;J. Wollschläger;M. Reichling;M. Bäumer;T. Schroeder
量身定制的CeO2/Pr2O3薄膜氧化物异质结构对表面科学技术在模型催化研究中的应用具有重要意义。为此，采用分子束外延技术在六价Pr2O3(0001)/Si(111)和CuB-Pr2O3(111)/Si(111)载体系统上生长了CeO2(111)薄膜。报道了用反射高能电子衍射、透射电子显微镜、实验室X射线衍射和同步辐射X射线衍射仪对其进行了比较严谨的结构研究。结果表明，在两种氧化物载体上均获得了无孪晶、纯B型取向的CeO2(111)薄膜。CeO2(111)薄膜采用CuB-Pr_2O_3(111)缓冲液的堆积顺序，但在六角形Pr2O_3(0001)薄膜中，堆积信息的传递不太明显。用从头算方法研究了CeO2(111)在Hex-Pr2O3(0001)/Si(111)体系中的异常堆积行为。结果表明，由于电子和结晶学因素的影响，B型堆积组态是较有利的组态，约为8 eV/nm2。
Tailored CeO2/Pr2O3 thin-film oxide heterostructures are of interest for model catalysis studies by surface science techniques. For this purpose, thin CeO2(111) films were grown by molecular beam epitaxy on hexPr2O3(0001)/Si(111) as well as on cub-Pr2O3(111)/Si(111) support systems. A comparative, rigorous structure investigation by reflection high-energy electron diffraction transmission electron microscopy and laboratory and synchrotron based x-ray diffraction is reported. It is found that twin-free, exclusively type-B oriented CeO2(111) films are obtained on both oxide supports. CeO2(111) films adopt the stacking sequence from the cub-Pr2O3(111) buffer, but the transfer of the stacking information is less evident in the case of hex-Pr2O3(0001) films. Ab initio calculations are applied to understand the unusual stacking behavior of the CeO2(111) on the hex-Pr2O3(0001)/Si(111) system. It is revealed that the type-B stacking configuration is the more favorable configuration by 8 eV/nm2 due to electronic and crystallographic factors.