NEAR-FIELD EMISSION SCANNING-TUNNELING-MICROSCOPY

The close proximity between probe and sample in a scanning tunneling microscope interface may produce unwanted modifications of the interface. This is particularly severe when working with soft materials, as molecular films or biomolecules. Here, we propose the operation of the scanning tunneling microscope in the near field emission regime as an effective method to overcome those problems. A theoretical description of the probe-sample interface in the near field emission regime predicts subatomic resolution in the direction normal to the surface and lateral resolution of 3 nm for tip-sample separations of 3-5 nm. Furthermore, atomic resolution is demonstrated by imaging steps of carbon atoms. © 1994 American Institute of Physics.