Extraction of electronic structural information on the grain-boundaries of Pd-based polycrystalline specimens with transmission electron energy loss spectroscopy

The grain-boundaries/surfaces play a vital role in the mechanical and electronic properties of a material. The importance of understanding their structure, therefore, cannot be overstressed. In a scanning transmission electron microscope, electron energy loss spectroscopy has long been used to study the electronic structure of the bulk material of a specimen while various efforts have been made to suppress the contribution to the spectrum from the surface electronic excitations. However, in this paper we demonstrate the possibility of extracting this surface loss component so as to obtain electronic structural information from the grain-boundaries/surfaces. This technique is applied to specimens of fresh and aged polycrystalline Pd films as well as a hydrogen-charged PdH polycrystalline film.