Characterization and First Results of an Inverse Photoemission Spectrometer

Abstract

This thesis discusses our efforts to characterize our home built inverse photoemission spectrometer. We review the relevant theoretical and practical considerations for the technique of inverse photoemssion spectroscopy. We then detail our efforts to characterize our low energy electron gun, presenting a method for determining the total current delivered by the beam using just a Faraday cup. Measurements of the beam’s profile are presented and are used to calculate the parallel momentum resolution of the beam. Equally important is the characterization of our photon detectors, which we show are operating in the proportional region with a minimal dark count rate. We ascertained a spectrometer energy resolution of 415(55) meV by performing inverse photoemission measurements on polycrystalline gold foil, single crystal Cu (111), and pyrolytic graphite. As a final demonstration of our spectrometer’s capabilities we provide a full unoccupied band mapping for pyrolytic graphite showing its ability to resolve dispersive electronic features in reciprocal space.