银纳米团簇在HOPG表面上的控制生长

由于银与高定向热解石墨(highly oriented pyrolytic graphite，HOPG)面间的相互作用很小，银在HOPG表面上的生长通常采取三维的Volmer-Weber模式，得到空间分布不均匀的银团簇。本文分别采用加热氧化和氩离子轰击来改变HOPG衬底的表面结构，并用扫描隧道显微镜(STM)研究了银在它们上面的生长过程。实验结果表明：在氩离子轰击过的HOPG表面上，可以得到大小基本一致、空间分布均匀的银纳米团簇，实现了银团簇的控制生长．氩离子轰击导致了平整的HOPG表面产生缺陷，这些缺陷对银原子的扩散进行限制并成为优先成核中心，最终形成均匀的银纳米团簇。

Controlled growth of uniform silver clusters on HOPG

Due to their high mobility and weak interaction with HOPG substrate, Ag atoms usually grow via the three-dimensional Volmer-Weber mode on HOPG and result in irregularly distributed silver clusters. To make uniformly sized and spaced Ag clusters, the HOPG surface was modified by thermal oxidization and Ar~+ sputtering before Ag deposition, respectively. Scanning tunneling microscopy (STM) observations revealed that uniformly sized and spaced Ag clusters could be formed on the sputtered surface. Ar~+ sputtering introduced relatively uniform surface defects. These defects served as preferential sites for Ag cluster nucleation and are found to be very important for the formation of uniform Ag clusters.