Surface Self-Diffusion of Iridium: Field Electron Emission Study

The self-diffusion of iridium was studied by means of field electron microscopy. The measurements, based on the well-known process of surface build-up, were carried out under the UHV conditions within the temperature range of 790-935K. The activation energy for the diffusion was determined to be equal to 2.10±0.10eV/atom (48.4±2.3kcal/mol). This value is compared with activation energies for self-diffusion on other metal surfaces, as well as with those for self-diffusion of single iridium atoms and clusters on iridium, known from the field ion microscopy measurements.