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The experimental and theoretical investigations of transition metal overlayers on solid surfaces have witnessed a rapid growth due to their widely technological application. Silicon is usually selected as a substrate due to well-developed techniques from semiconductor technology. However, the interface between transition metal and Si is so reactive as to form metal silicide, which is regarded as an origin of the disappearance of ferromagnetism. Growth of silver on Si (111) has attracted much attention for the past two decades; now this surface is regarded as a prototypical metal-covered semiconductor system and is used as a unique substrate for the growth of molecular layers, adatom gas phase and other surface superstructures by additional metal and hydrogen adsorptions. In this work, we have used the Ag(√3×√3)/Si(111) surface as an template for growing Co nanoplatelets. Ag(√3×√3) surface has been fabricated on clean Si(111) surface at 530 ± 5 °C. Subsequently, 0.4 ML Co has been evaporated on the template at 520 ± 5 °C substrate temperature and a deposition rate of ~ 0.07 ML/min (1ML = 7.83×1014 Co atoms/cm2, the number of top layer Si atoms for Si(111) 1×1 surface per cm2). STM image shows that Co islands with large distributions of size and height has been obtained. Among these Co islands, most of them have a triangle or a hexagon shape with height of 0.9 nm to 2.4nm, on which STM image with atomic resolution shows quasi-periodic structure. Also, there are a little lager irregular islands with height of ~0.15 nm (nearly half of the Si (111) surface step), on which STM image shows self-assembed quasi-periodic trimer structure. In this presentation we will base on IET mode of Ag (√3× √3)/Si(111) surface to discuss this kind of trimer structure. |