论文部分内容阅读
迄今非接触原子力显微镜已经成为一个非常强大的工具.它不仅能够得到表面的原子周期结构,还能给出分子内部的化学键信息.针尖和样品之间的相互作用是原子力显微镜的有效信号,主要包括三种,即范德瓦尔斯相互作用、静电相互作用和化学键相互作用.本文在生长于Si(111)-7×7的铅薄膜上测量了针尖和样品之间的化学键相互作用.通过获取该相互作用随偏压的变化,并且利用抛物线拟合有效局域接触势的位置,我们发现它是随着针尖和样品之间距离的增大而减小的.这种趋势来自于针尖和样品之间波函数的交叠.从而可以得到电子的衰减长度.我们还测量到了该衰减长度随着铅薄膜厚度的变化会发生振荡,这种振荡归因于平顶楔形铅岛内电子的量子尺寸效应.
So far, non-contact atomic force microscopy has become a very powerful tool not only to get the surface atomic periodic structure, but also to give chemical bond information inside the molecule.The interaction between tip and sample is an effective signal of AFM, mainly including Three kinds, namely Van der Waals interaction, electrostatic interaction and chemical bond.In this paper, the chemical bond interaction between the tip and the sample was measured on a lead film grown on Si (111) -7 × 7. By obtaining the Interaction With the change of bias voltage, and using the parabola to fit the location of the effective local contact potential, we find that it decreases as the distance between the tip and the sample increases .This trend comes from the tip and the sample We found that the decay length oscillates with the thickness of the lead film due to the quantum size effect of the electrons in the flat wedge-shaped lead islands .