Fabrication of sharp atomic force microscope probes using in-situ local   electric field induced deposition under ambient conditions
  We demonstrate a simple method to significantly improve the sharpness of standard silicon probes for an atomic force microscope, or to repair a damaged probe. The method is based on creating and maintaining a strong, spatially localized electric field in the air gap between the probe tip and the surface of conductive sample. Under these conditions, nanostructure growth takes place on both the sample and the tip. The most likely mechanism is the decomposition of atmospheric adsorbate with subsequent deposition of carbon structures. This makes it possible to grow a spike of a few hundred nanometers in length on the tip. We further demonstrate that probes obtained by this method can be used for high-resolution scanning. It is important to note that all process operations are carried out in-situ, in air and do not require the use of closed chambers or any additional equipment beyond the atomic force microscope itself. 
Alexei Temiryazev, Sergey I. Bozhko, A. Edward Robinson, and Marina   Temiryazeva
cond-mat.mes-hall