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低能Ar+溅射诱导CeO2(111)薄膜还原

发表时间:2012-04-15  浏览量:1147  下载量:398
全部作者: 王国栋,孔丹丹,潘永和,潘海斌,朱俊发
作者单位: 中国科学技术大学国家同步辐射实验室
摘 要: 利用同步辐射光电子能谱(synchrotron radiation photoemission spectroscopy, SRPES)原位、系统地研究Ar+溅射对在Ru(0001)表面外延生长的CeO2(111)薄膜表面的电子结构和化学成分的影响。结果表明:在1 keV和0.5 μA/cm2的Ar+溅射条件下,Ar+溅射引起费米能级以下1.6 eV处出现Ce3+特征的Ce 4f1峰,归结为CeO2表面的Ce4+被还原成Ce3+. 随着溅射时间的增加,还原态Ce3+的峰强度也逐渐增强。15 min后,当溅射到样品表面的Ar+面密度达到2.8×1015 ions/cm2时,还原态Ce3+的峰强度不再增加,生成Ce3+的数量基本达到饱和。Ar+溅射诱导CeO2表面被还原,是由于样品表面的氧原子被优先刻蚀而引起的。经过15 min的Ar+溅射,样品表面形成了大约0.74 nm的CeO2-x层。得到结论:Ar+溅射是一种使CeO2表面还原成CeO2-x的有效方法,样品表面的还原程度主要取决于溅射Ar+的能量和数量。
关 键 词: 物理化学;Ar+溅射;同步辐射;CeO2;优先刻蚀
Title: Reduction of CeO2(111) film by low energy Ar+ sputtering
Author: WANG Guodong, KONG Dandan, PAN Yonghe, PAN Haibin, ZHU Junfa
Organization: National Synchrotron Radiation Laboratory, University of Science & Technology of China
Abstract: The structure and electronic properties of epitaxial grown CeO2(111) thin films before and after Ar+ bombardment have been systematically studied in situ with synchrotron radiation photoemission spectroscopy (SRPES). Under the condition of the energy of Ar ions being 1 keV and a constant current density of 0.5 μA/cm2, Ar+ bombardment of the surface causes a new emission appearing at 1.6 eV above the Fermi edge, which is related to the localized Ce 4f1 orbital in the reduced oxidation state Ce3+. With increasing time of sputtering, the intensity of the reduced state Ce3+ increases and reaches a constant value after 15 min sputtering, which corresponds to the surface being exposed to 2.8×1015 ions/cm2. The reduction of CeO2 is attributed to a preferential sputtering of oxygen from the surface. Ar+ bombardment leads to a gradual buildup of an, approximately 0.74 nm thick, sputtering altered layer after 15 min sputtering. These studies have demonstrated that Ar+ bombardment is an effective method for reducing CeO2 to CeO2-x and the degree of the reduction is related to the energy and amount of Ar ions been exposed to the CeO2 surface.
Key words: physical chemistry; Ar+ sputtering; synchrotron radiation; cerium oxide; preferential sputtering
发表期数: 2012年4月第7期
引用格式: 王国栋,孔丹丹,潘永和,等. 低能Ar+溅射诱导CeO2(111)薄膜还原[J]. 中国科技论文在线精品论文,2012,5(7):607-614.
 
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