XPS Studies of Bi-Sr-Ca-Cu-O Single Crystal and Ceramics Surfaces

Abstract

The XPS (X-ray photoelectron spectroscopy) spectra from (a) the cleaved surface of a single crystal, (b) the polished surface and (c) the Ar+-sputtered surface of the ceramics in Bi-Sr-Ca-Cu-O are mecnsured and compared. The chemical bond nature of Bi is the same in all three surfaces. Sr and Ca in (c) are more oxidized than those in (a). In (b), there are two kinds of Sr and Ca, one from a clean surface like the cleaved surface region, and the other, more oxidized Sr and Ca which exist in the Ar+-sputtered surface. Cu2+ is dominant in (a) and (b), while Cu+ is dominant in (c). The O 1s XPS spectrum from (c) is sharper and narrower than that from (a). This may be due to the existence of isolated metal oxides of Sr, Ca and Cu by Ar+-sputter etching.