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Electronic Properties of Singvle-Crystal Oxide Films Fabricated on Metal Surfaces

金属表面单晶氧化膜的电子特性

基本信息

批准号：
11440090
负责人：
MURATA Yoshitada
金额：
$ 10.18万
依托单位：
The University of Electro-Communications
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11440090/
关键词：
α-alumina β-quartz single-crystal oxide films single-crystal metals band gap narrowing many-body effect monolayer film of platinum grazing incidence X-ray diffraction アルミナシリカ単結晶酸化物薄膜層状成長一酸化炭素吸着 α-Al_2O_3 β-SiO_2 単結晶薄膜バ

项目摘要

High-quality single-crystal films of α-Al_2O_3 9A thick and SiO_2 30 A thick have been fabricated on metal surfaces of Ru(0001) and Ni(111), respectively. α-Al_2O_3 was fabricated by a phase transition from γ- to α-Al_]2O_3 having a commensurate structure with Ru(0001). Atomic hydrogen during initial growth of an amorphous SiO_2 film and ambient oxygen atmosphere during annealing of this film were essential in forming the single-crystal SiO_2 film on Ni(111). An extraordinary result that the band gap for the oxide layer decreases with decreasing oxide thickness was preliminarily observed using scanning tunneling spectroscopy (STS). This result was confirmed by medium-resolution electron energy loss spectroscopy, in. which the oxide thickness V. dependence of the band gap was measured by α-Al_2O_3 films with various oxide thicknesses below 35 A. For growing ultra-thin films of transition metals on a single-crystal oxide, i.e. a wide band gap crystal, we have, utilized the band gap narrowing and succeeded in making a monoatomic layer (ML) of a Pt film on α-Al_2O_3(9 A)/Ru(0001). We have investigated electronic properties of the oxide layer using C-O vibrational frequencies of CO adsorbed on Pt(1 ML)/α-Al_2O_3(9 A)/Ru(0001) measured by reflection absorption infrared spectroscopy. On the other hand, the crystal structure of SiO_2 film thick 40 A was investigated by grazing incidence X-ray diffraction using syncrotron radiation. A nice single crystal film of β-quartz is fabricated with a thickness of 30 A and a polycrystalline Ni silicide film 10 A thick is formed with a mosaic structure at the interface. These single-crystal oxide films on metal surfaces are new surface materials, which will open a window against other fields of solid state physics and chemistry.

在Ru（0001）和Ni（111）金属表面分别制备了厚为9A和30 A的高质量α-Al_2O_3和SiO_2单晶薄膜。α-Al_2O_3是由γ-Al_2O_3向α-Al_2O_3的相变生成的，具有与Ru（0001）相当的结构。在Ni（111）衬底上，非晶SiO_2薄膜生长初期的氢原子和退火时的氧气氛是形成单晶SiO_2薄膜的必要条件。利用扫描隧道谱（STS）初步观察到氧化层的带隙随氧化层厚度的减小而减小的异常结果。这一结果证实了中分辨率电子能量损失谱，在。用不同氧化层厚度的α-Al_2O_3薄膜测量了带隙随氧化层厚度的变化关系。为了在单晶氧化物即宽带隙晶体上生长过渡金属超薄膜，我们利用带隙变窄的原理，成功地在α-Al_2O_3（9A）/Ru（0001）上制备了Pt膜的单原子层（ML）。用反射吸收红外光谱法研究了Pt（1 ML）/α-Al_2O_3（9A）/Ru（0001）上CO的C-O振动频率。另一方面，利用同步辐射掠入射X射线衍射研究了40埃厚SiO_2薄膜的晶体结构。制备了厚度为30埃的β-石英单晶膜，并在界面处形成了具有镶嵌结构的10埃厚的多晶镍硅化物膜。金属表面的单晶氧化物薄膜是一种新型的表面材料，它将为固体物理和化学的其他领域打开一扇窗。