X-ray and UV photoemission from defects in LiNb03and BaTi03surfaces

Abstract
The electronic structure of LiNb03 and BaTi03 single crystal surfaces have been studied by X-ray and UV photoemission spectroscopy. Band-gap defect emission has been observed from Ar ion bombarded surfaces, which are disordered and oxygen deficient. Electron heating restores the upper surface layers but creates bulk defect states. The core level spectra from LiNb03 show that Nb4+ ions and Li and 0 vacancies are created during electron bombardment. The bulk band-gap defect state in LiNb03 can be interpreted as a 4d electron state.