Observation of local photoemission using a scanning tunneling microscope

Abstract

We report photoelectron emission characteristics from cesiated gold (110) surfaces illuminated by photons using the tip of a scanning tunneling microscope as a local probe. An analysis of tip current as a function of applied bias permits determination of the maximum kinetic energy of impinging photoelectrons whose value is in good agreement with an independent analysis based on macroscopic measurements of the surface workfunction. Based on our preliminary results, possible schemes for the fabrication of local probe photoelectron analysers for use with synchrotron or laser illumination are developed. Additional physical considerations suggest that liquid environments should in particular introduce a useful exponential dependence of the elastic photoemission signal intensity on tip-surface separation. © 1992.