Formation of (n x 1)-O/Ag(110) overlayers and the role of step-edge atoms.
Formation of (n x 1)-O/Ag(110) overlayers and the role of step-edge atoms.
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(n x 1)-O/Ag(110) 覆盖层的形成和阶梯边缘原子的作用。
DOI：
10.1103/physrevb.53.15997
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发表时间：
1996
影响因子：
3.7
通讯作者：
R. Je
中科院分区：
文献类型：
--
作者：
Pai Ww;R. Je
采用超高真空扫描隧道显微镜研究了Ag（110）对氧的吸附。强有力的证据表明，n× 1), n= 7，…(2)氧覆盖层采用类似于（2× 1）-O/Cu（110）体系的“加排”结构。由于Ag（110）上的氧“添加行”是位于原始底物之上的a-Ag- o -Ag链状结构，因此底物原子的来源必须存在。原则上，只要台阶边缘的分离速率足够大，台阶就可以作为这些底物原子的有效来源。当氧分压较低时，标称剥离速率（每步位约3个Ag原子/s）足以提供形成加行结构的原子。对于高氧压力（~ p2o ~ 10−5 mbar），解离氧化学吸附的速率与台阶分离的银供应速率是竞争的，而银原子的第二个来源是梯田上的空岛生成。O/Ag（110）的氧层微观结构与O/Cu（110）和O/Ni（110）的氧层微观结构非常相似，但在形成动力学上存在一些差异。©1996美国物理学会。
Oxygen adsorption on Ag (110) was studied by ultrahigh vacuum scanning tunneling microscopy. Strong evidence that the n× 1), n= 7,..., 2, oxygen overlayers adopt an ‘‘added-row’’structure similar to the (2× 1)-O/Cu (110) system is presented. Since the oxygen ‘‘added row’’on Ag (110) is a-Ag-O-Ag-chainlike structure atop the original substrate, a source of the substrate atoms must exist. Steps, in principle, serve as an efficient source of these substrate atoms, provided that the detachment rates from the step edges are sufficiently large. The nominal detachment rate (∼ 3 Ag atoms/s per step site) is sufficient to supply atoms to form the added-row structure when the oxygen partial pressure is low. For high oxygen pressures (∼ P O 2≳ 10− 5 mbar), the rate of dissociative oxygen chemisorption is competitive with the Ag supply rate from step detachments, and a second source of Ag atoms is provided by vacancy-island generation on the terraces. The microscopic structure of the oxygen overlayer of O/Ag (110) is quite similar to those of O/Cu (110) and O/Ni (110), but some differences in the formation kinetics are noted.© 1996 The American Physical Society.