Surface characterisation of strontium-bismuth tantalate (SBT) thin films

A review of electronic structural data is given and an interface Schottky m odel has been developed. X-ray photoemission spectroscopy (XPS) and seconda ry electron emission data have been used to determine the electron affinity of SBT and the band match-up for the SBT/Pt junction. The results of X-ray absorption spectroscopy studies and XPS valence band measurements indicate d the electronic states above and below the bandgap of SBT. These experimen tal data have been compared with the results of tight-binding calculations. Angle dependent XPS measurements indicated that metallic bismuth is diffus ing to the surface of SBT which would have significant influence on the ele ctrical properties of the SBT/Pt junction. The hydrogen distribution in SBT , also an important issue for the device properties, has been probed using elastic recoil detection.