Investigation of surface potential distributions of phosphorus-doped n-BaSi₂ thin-films by Kelvin probe force microscopy

Abstract

We investigated the surface potential distributions around grain boundaries (GBs) in phosphorus (P)-doped n-BaSi₂ thin-films by Kelvin probe force microscopy (KFM) and the crystal planes constituting GBs by transmission electron microscopy (TEM). By KFM measurements, it was found that the GBs in P-doped n-BaSi₂ are different from those in undoped BaSi₂; undoped n-BaSi₂ has a downward band bending around the GBs with barrier heights of approximately 30 meV. In contrast, P-doped n-BaSi₂ has an upward band bending with barrier heights of approximately 15 meV. TEM observation revealed that most of the GBs in P-doped BaSi₂ are composed of BaSi₂ (011)/() planes. This result is the same as that in undoped BaSi₂.