The Tetrahedral Tip as a Probe for Scanning Near-Field Optical and for Scanning Tunneling Microscopy

Abstract

It was recently shown, that the tetrahedral tip can be used as a probe for Scanning Near- Field Optical Microscopy (SNOM) at a lateral resolution of 30 nm. The optical signal as obtained in an Inverse Photon Scanning Tunneling Microscope configuration was used to control the distance between tip and object during the scan. The optical signal is however not only determined by the distance between tip and object. To explore the resolution limits of our SNOM we need an independent signal for controlling the distance during a scan more accurately. We tested the possibility to use the tetrahedral tip for simultaneous SNOM and STM operation by using the tetrahedral tip as a probe for STM alone. In first experiments atomic resolution was obtained on graphite, and a resolution in the nm range, superior to the one obtained by us in AFM images could be demonstrated on test samples, which are comparable to the ones used for the SNOM experiments.