Morphology of Monolayer MgO Films on Ag(100): Switching from Corrugated Islands to Extended Flat Terraces
Morphology of Monolayer MgO Films on Ag(100): Switching from Corrugated Islands to Extended Flat Terraces
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DOI：
10.1103/physrevlett.112.126102
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发表时间：
2014-03-26
影响因子：
8.6
通讯作者：
Rocca, Mario
中科院分区：
文献类型：
--
作者：
Pal, Jagriti;Smerieri, Marco;Rocca, Mario
设计近乎完美的超薄氧化层的能力，达到单层厚度的极限，是纳米技术应用的关键问题。在这里，我们面临着Ag（100）上超薄MgO薄膜的困难和重要的情况，迄今为止，在单层限制下，没有延伸和有序的层可以产生。我们证明了它们的最终形态不仅取决于通常的生长参数（晶体温度、金属通量和氧分压），而且还取决于生长后处理，控制迄今为止被忽视的热力学约束。因此，我们成功地调整了氧化膜的形状，从不规则的、纳米大小的、单层厚的岛到稍大的、完全正方形的、双层岛，再到显然只受衬底步骤限制的扩展单层。
The ability to engineer nearly perfect ultrathin oxide layers, up to the limit of monolayer thickness, is a key issue for nanotechnological applications. Here we face the difficult and important case of ultrathin MgO films on Ag(100), for which no extended and well-ordered layers could thus far be produced in the monolayer limit. We demonstrate that their final morphology depends not only on the usual growth parameters (crystal temperature, metal flux, and oxygen partial pressure), but also on aftergrowth treatments controlling so far neglected thermodynamics constraints. We thus succeed in tuning the shape of the oxide films from irregular, nanometer-sized, monolayer-thick islands to slightly larger, perfectly squared, bilayer islands, to extended monolayers limited apparently only by substrate steps.