A theoretical calculation of the electrical characteristics of the NFESE Microscopy

In the Near Field Scanning Electron Microscopy recently developed the tip of the microscope is placed a few tens of nm away from the anode. Measurements of voltage with respect to the tip-anode distance at constant current have been taken by Kirk et al. We have used a 3-dimensional WKB approximation to simulate these measurements. Our results are consistently 5-10 volts below the experimental ones. This was attributed to a thin WO₃ layer on the tip which we have not taken into account.