Electron Emission from High-Purity Copper Wires

Abstract

Field electron emission measurements were carried out on copper of 99.95% purity emitters, with apex radii in the nano and micrometer range. Samples have been prepared by electrochemical etching using phosphoric acid (H₃PO₄) solution. Measurements have been carried out under high vacuum environments with a base pressure of 10^-7 mbar. Samples were installed in a field electron microscope (FEM) with an anode (tip)-to-cathode (screen) distance of 10 mm. Scanning electron microscope images, electrons spatial distribution behavior, and the current-voltage characteristics (I-V) have been studied and analyzed. Copper emitters have been prepared as electron sources and tested. The results showed a typical current-voltage characteristic from a coat emitter. The scanning electron microscope showed the sample geometry and cleanness. These copper electron emitters have been found to have significant aspects (high voltage breakdown mechanism) affecting the performance of advanced systems such as the electronic accelerator of The European Organization for Nuclear Research, known as CERN. This work aims to study this type of material to understand the high voltage breakdown phenomena in copper and the reasons behind it to provide a solution to such phenomena.