【摘要】 利用超高真空扫描隧道显微镜 (UHVSTM)研究了室温条件下沉积在Si(111) 7× 7重构表面不同覆盖度的Ag粒子。实验结果表明 ,低覆盖度时的Ag粒子主要有A、B两种类型 ,其中A型Ag粒子呈环状结构 ,最小的A型Ag粒子由 3个Ag原子组成 ;而B型Ag粒子则是由两层Ag原子构成。高覆盖度时Ag粒子的生长过程为层岛混合生长 (Stranski Krastanov)模式。本文还研究了不同蒸发速率对Ag原子成核的影响 ,发现在高蒸发速率条件下Ag原子在Si(111) 7× 7重构表面更容易成核。更多还原

【Abstract】 Silver (Ag) clusters,deposited on the Si(111) 7×7 reconstruction surface at roo m temperature,were studied with ultrahigh vacuum scanning tunneling microscpoy ( UHV-STM).The results indicated that two types of Ag clusters exist at low cover age.A-type Ag clusters display ring-like structures and the smallest one inclu ded 3 Ag atoms;B-type Ag clusters are composed of 2 layers of Ag atoms.At high coverage,Ag clusters grow in the Stranski-Krastanov mode.Influence of the evap oration rate on the nucleation of Ag atoms was also studied,and we found that it was easier for Ag atoms to nucleate on the faulted half unit cell at high evapo ration rate than that at low evaporation rate.更多还原