Modifying the STM Tip for the ' Ultimate ' Imaging of the Si(111)-7×7 Surface and Metal-supported Molecules

Authors

  • Ye-liang Wang Chinese Academy of Sciences, Institute of Physics, Beijing 100190, China. ylwang@iphy.ac.cn
  • Zhi-hai Cheng Chinese Academy of Sciences, Institute of Physics, Beijing 100190, China
  • Zhi-tao Deng Chinese Academy of Sciences, Institute of Physics, Beijing 100190, China
  • Hai-ming Guo Chinese Academy of Sciences, Institute of Physics, Beijing 100190, China
  • Shi-xuan Du Chinese Academy of Sciences, Institute of Physics, Beijing 100190, China
  • Hong-jun Gao Chinese Academy of Sciences, Institute of Physics, Beijing 100190, China. hjgao@iphy.ac.cn

DOI:

https://doi.org/10.2533/chimia.2012.31

Keywords:

High resolution, Molecule, Si(111)-7×7, Stm, Tip

Abstract

We report on high-resolution STM measurements with modified probe tips. First, both the rest atoms and adatoms of a Si(111)-7×7 surface are observed simultaneously. The visibility of rest atoms is dependent upon the sample bias voltage (less than –0.7 V) and is enhanced by sharpening the tip, which is rationalized by first-principles calculations. Second, a tip with a perylene molecule adsorbed at its apex is used to discriminate the molecular states and the metal states of the underlying Ag(110) surface, which is attributable to a mismatch between the energy levels of the functionalized tip and the adsorbates on silver. Lastly, high-resolution images of iron phthalocyanine (FePc) and zinc phthalocyanine (ZnPc) molecules on Au(111) are obtained by using an O2-terminated tip, and the images reveal rich intramolecular features arising from molecular orbitals that are not observed when using clean metallic tips.

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Published

2012-02-29

How to Cite

[1]
Y.- liang Wang, Z.- hai Cheng, Z.- tao Deng, H.- ming Guo, S.- xuan Du, H.- jun Gao, Chimia 2012, 66, 31, DOI: 10.2533/chimia.2012.31.