Chemical Reactivity at Mo/CuO Interface

The technique of x-ray photoelectron spectroscopy has been used to investigate the chemical reactivity at the Mo/CuO. Thin films of molybdenum were deposited on CuO substrates kept at room temperature by the e-beam method. The thickness of the molybdenum film was varied between 3 Å and 10 Å. The molybdenum 3d, oxygen 1s, and copper 2p regions were investigated. The spectral data show the absence of the high binding energy satellite in the copper 2p regions. This corresponds to the reduction of CuO to elemental copper. The molybdenum overlayer is observed to get oxidized to MoO₃. The thickness of oxidized molybdenum was found to depend upon the initial thickness of the molybdenum overlayer. The reaction is observed to continue until the molybdenum overlayer exceeds a thickness of 7 Å. Beyond this thickness unreacted molybdenum is observed. The width of the interface has been estimated from the spectral data. The study provides a means of preparing nano-dimensional MoO₃.