The adhesion and interface chemistry of ion-plated selenium

A combination of fracture measurements and photoelectron spectroscopy has been used to investigate the bond strength of selenium evaporated onto α-brass substrates. Failure of thermally evaporated deposits occurs at an SeCuO interface layer even though selenium is chemically bonded to the oxide. It is shown that the interface oxide complex is removed during an ion plating process and that as a consequence the Se-brass bond strength increases significantly. However, the bulk adhesion properties of thermally deposited and ion-plated specimens are found not to be significantly different. This anomaly is discussed in terms of crack propagation, dispersion of the interface oxide during ion plating and failure at a new highly bonded CuSe interface layer.