Distance dependence of atomic-resolution near-field imaging on alpha-Al2O3 (0001) surface with respect to surface photovoltage of silicon probe tip

作者：Yamanishi Junsuke; Tokuyama Takashi; Naitoh Yoshitaka; Li Yan Jun; Sugawara Yasuhiro^*

来源：Nano Research, 2016, 9(2): 530-536.

DOI：10.1007/s12274-015-0934-4

• near-field scanning optical microscopy
• near field
• surface photovoltage
• alpha-Al2O3 (0001)
• force detection

Recently, we achieved atomic-resolution optical imaging with near-field scanning optical microscopy using photon-induced force detection. In this technique, the surface photovoltage of the silicon-tip apex induced by the optical near field on the surface is measured as the electrostatic force. We demonstrated atomic-resolution imaging of the near field on the alpha-Al2O3 (0001) surface of a prism. We investigated the spatial distribution of the near field by scanning at different tip-sample distances and found that the atomic corrugation of the near-field signal was observed at greater distances than that of the atomic force microscopy signal. As the tip-sample distance increased, the normalized signal-to-noise ratio of the near field is in a gradual decline almost twice that of the frequency shift (Delta f).

• 出版日期2016-2