Ag在Si(100)表面化学吸附特性研究

Investigation for Chemisorption of Ag on Si(100) Surface

本文应用自洽TB-LMTO方法研究银原子在理想Si(100)表面的化学吸附,计算不同位置的吸附能量(Ead),发现相比Si(100)表面其他吸附位置而言被吸附的银原子更趋附于C位置(四重位),在Ag原子和表面Si原子之间形成极性共价健,在Ag-Si(100)界面不存在Ag和Si的混合层而是形成突变界面,这与实验结果是一致,计算了层投影态密度并与清洁表面比较,对电子转移情况也进行了研究.相对Au/Si(100)而言,Ag和Si相互作用比Au和Si相互作用要弱.

The chemisorption of one monolayer Ag atoms on an ideal Si （100） surface is studied by using the self- consistent tight binding linear muffin - tin orbital method. The adsorption energies （Ead） of different sites are calculated. It is found that the adsorbed Ag atoms are more favorable on C site （fourfold site） than on any other sites on Si（100） surface, the polar covalent bond is formed between Ag atom and surface Si atom, a Ag and Si mixed layer does not exist and does form an abrupt interface at the Ag- Si （100） interface. This is in agreement with the experimental results. The layer projected density of states is calculated and compared with that of the clean surface, and the charge transfer is also investigated. Comparing with the Au/Si（100） system, the interaction is weaker between Ag and Si than between Au and Si.