An XPS study of zinc oxide thin film growth on copper using zinc acetate as a precursor

Ultrathin zinc oxide (ZnO) films (10–200 Å thickness range) were grown on polycrystalline copper substrates via the sublimation of anhydrous zinc acetate (Zn(CH3COO)2) in high vacuum (5 × 10−7mbar). The thermal decomposition of basic zinc acetate precursor films, deposited on room temperature substrates, to ZnO were examined using X-ray photoelectron spectroscopy (XPS). The transformation to ZnO was monitored as a function of post-deposition sample heating, up to temperatures of 350 °C. ZnO films were grown on copper substrates heated to 400 °C and analysed using angle-dependent XPS and depth profiling. These films were found to contain less than 4% atomic carbon in the bulk and there was no direct evidence for island-type growth.