X-ray Photoelectron Spectroscopy Study of the Clean Surface of Bi-Based Single Crystals.

We heated the Bi2Sr2Can-1CunOy (BSCCO) single crystals in air and investigated their surfaces with X-ray photoelectron spectroscopy (XPS). From the results, we found that the clean surface, where carbon and oxygen impurities were not included, was obtained by heating the BSCCO single crystal at 400-500°C in air for 1 h. In addition, any deterioration of the BSCCO single crystal surface does not occur by the heat-treatments in the chemical composition and state of the surface.