Well-Ordered Molybdenum Oxide Layers on Au(111): Preparation and Properties
Well-Ordered Molybdenum Oxide Layers on Au(111): Preparation and Properties
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DOI：
10.1021/jp3113792
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发表时间：
2013-05-02
影响因子：
3.7
通讯作者：
Freund, H. -J.
中科院分区：
文献类型：
--
作者：
Guimond, S.;Goebke, D.;Freund, H. -J.
在Au（111）上的MoO 3层通过在50 mbar的O-2气氛中在高温下氧化钼来制备。确定了三种不同类型的氧化物结构。直到单层氧化物覆盖，相对于Au（111）晶胞形成具有c（4 x 2）晶胞的结构。这种结构先前被鉴定为类似于α-MoO 3的单层。(1)在高达两层的较大覆盖率下，出现具有11.6埃x5埃矩形晶胞的氧化物。覆盖率的进一步增加导致出现具有非常小的缺陷密度的规则α-MoO 3的微晶。这些微晶以平行于衬底表面的（010）平面和随机方位角取向生长，导致LEED图案中的环。随着层厚度的增加，微晶开始聚结，直到最终形成封闭的膜。这些层升华在约670和770 K之间的温度与MoO 3聚集体升华在较低的温度比双层和单层膜。
MoO3 layers on Au(111) were prepared via oxidation of molybdenum at elevated temperature in an atmosphere of 50 mbar of O-2. Three different types of oxide structures were identified. Up to monolayer oxide coverage a structure with a c(4 x 2) unit cell relative to the Au(111) unit cell forms. This structure was previously identified as being similar to a monolayer of alpha-MoO3.(1) At larger coverages of up to two layers an oxide with a 11.6 angstrom x 5 angstrom rectangular unit cell appears. Further increase in the coverage leads to the occurrence of crystallites of regular alpha-MoO3 with a very small density of defects. These crystallites grow with the (010) plane parallel to the substrate surface and with random azimuthal orientation leading to rings in the LEED pattern With increasing layer thickness the crystallites start to coalesce until finally a closed film forms. These layers sublimate at temperatures between about 670 and 770 K with the MoO3 aggregates sublimating at lower temperature than the bilayer and monolayer films.