Nanometer-Scale Qualitative Analysis of Surfaces With a Modified Scanning Tunneling Microscope/ Field Emission Source

Abstract

We have designed and constructed modifications to the scanning tunneling microscope that allow the bias voltage to be used as an excitation source for arc atomic emission spectroscopy. The purpose of this addition to the instrument is to allow unambiguous elemental analysis of species present on the surface. The light emitted from the arc across the tunneling gap is collected by appropriate means (such as optical fibers positioned in close proximity to the tip) and directed into a high resolution spectrometer for spectral analysis by a multichannel detector (such as a charge-coupled device (CCD) or photodiode array). Present progress includes completion of the hardware and software modifications to the instrument, verification of emission and verification that the light is substantively collected into optical fibers using a scheme described in this paper.