An experimental study of the electronic structure of anodically grown films on an amorphous Ni78Si8B14 alloy

Films of Ni(OH) 2 and NiOOH grown on a rapidly solidified amorphous Ni 78 Si 8 B 14 alloy by anodic polarisation were analysed with XPS and the results were compared with those of NiO and of films grown on polycrystalline Ni. SIMS performed on the polarised alloy showed enrichment of Ni at the outermost surface. Transmission electron microscopy (TEM) of cross-sectional samples showed an absence of crystallinity. The Ni 2p shake up satellite and valence band spectra suggested that NiOOH is characterised by a more enhanced n-type semi-conducting behaviour compared to Ni(OH) 2 in agreement with earlier tunnelling current density measurements performed with scanning tunnelling spectroscopy (STS).