Near surface composition of some alloys by X-ray photoelectron spectroscopy

Chemical compositions of the alloys of CuNi (Cu0.10Ni0.90, Cu0.30Ni0.70, Cu0.70Ni0.30) and BiSb (Bi0.80Sb0.20, Bi0.64Sb0.34, Bi0.55Sb0.45) are determined by X-ray photoelectron spectroscopy. The stoichiometries are determined and are compared with the bulk compositions. Possible sources of systematic errors contributing to the results are discussed. Errors arising out of preferential etching in these alloys have been investigated. It has been inferred from such studies that the preferential etching does not enrich the surface composition with a particular component for the two systems reported here. Quantitative results of CuNi system indicate that the surface regions of the Cu0.70Ni0.30 alloy is Cu-rich, although no such evidence is observed in case of BiSb system.