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Digital Control of Terrace Width of One-dimensional Semiconductor Surfaces by Modification of Lattice Strain

通过修改晶格应变数字控制一维半导体表面的平台宽度

基本信息

批准号：
12450024
负责人：
YOSHIMURA Masamichi
金额：
$ 5.38万
依托单位：
Toyota Technological Institute
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

The clean Si (110) surface shows a "16x2" reconstruction, where one-dimensional up-and-down terraces arrange alternatively. The terrace width is about 2.5 nm and the height difference between the adjacent terraces is one atomic layer, 0.2 nm. This surface is a promising substrate for future low-dimensional electronic devices as well as nano-biomaterials. In this study, we have tried to control the terrace width by a unique method using metal adsorption. This is based on the idea that the surface stress plays a role to determine the surface step density. The metal we used is a tin, which belongs the same periodic table as silicon, because homovalent doping does not so much affect electronic structures on the surface. At 0.2 ML adsorption of Sn on the surface, the 16x2 changed into 28x2, which was confirmed by low-energy electron diffraction as well as scanning tunneling microscopy. STM observation shows that Sn atoms forms trimers which are inserted accordingly into the silicon pentagonal clusters. As a result, surface stress was reduced to make the terrace width being enlarged to about 50%. In addition of structural point of view, we attempted to modify electronic nature of the up-and-down terraces by hydrogen termination technique. The result shows that, at the initial stage of reaction, atomic hydrogen reacts with specific atoms in pentagonal cluster to reduce surface stress, and that the up-and-down structure is kept at a saturation coverage of hydrogen, demonstrating the potential of this surface even in air. Ag and Ba deposition on Si(110) are now in progress

清洁的Si(110)表面呈现出“16×2”的重构，其中一维上下梯级交替排列。梯田的宽度约为2.5 nm，相邻梯田之间的高度差为一个原子层，0.2 nm。这种表面很有希望成为未来低维电子器件和纳米生物材料的衬底。在这项研究中，我们试图通过一种独特的方法来控制梯田的宽度，这种方法是利用金属吸附来实现的。这是基于表面应力对表面台阶密度起决定作用的思想。我们使用的金属是锡，它与硅属于同一元素周期表，因为同价掺杂不会对表面的电子结构产生太大影响。低能电子衍射和扫描隧道显微镜证实，当锡在表面吸附0.2ML时，16x2转变为28x2。STM观察表明，锡原子形成三聚体，并相应地插入到硅五方团簇中。结果，降低了表面应力，使梯田宽度扩大到50%左右。除了结构上的观点外，我们还尝试通过氢终止技术来改变上下阶梯的电子性质。结果表明，在反应的初始阶段，氢原子与五角团簇中的特定原子发生反应以降低表面应力，并且上下结构保持在氢的饱和覆盖下，这表明该表面即使在空气中也是潜在的。在Si(110)衬底上沉积银和钡目前正在进行中