AVS 50th International Symposium
    Thin Films Tuesday Sessions
       Session TF-TuA

Paper TF-TuA1
Enhanced Conductivity in Post Deposition Annealed Spinel Oxide Films

Tuesday, November 4, 2003, 2:00 pm, Room 329

Session: Transparent Conducting Oxides
Presenter: R.R. Owings, University of Florida
Authors: G.J. Exarhos, Pacific Northwest National Laboratory
R.R. Owings, University of Florida
C.F. Windisch, Pacific Northwest National Laboratory
P.H. Holloway, University of Florida
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Infrared transparent nickel cobalt spinel oxides exhibit p-type polaron conductivity that is highly dependent on the content of nickel in the structure. In this system, the relatively high covalency of nickel and the distribution of cation oxidation states among the available tetrahedral and octahedral lattice sites act to promote polaron formation. The nature of the polaron formed and its mobility are very much dependent upon composition and lattice parameter which, in turn, can be altered by choice of deposition parameters and post deposition treatment. Film conductivity is affected directly by post deposition annealing and can be enhanced or degraded reversibly upon rapid quenching or slow cooling to produce a set of recoverable conductivity values. The addition of lithium into the nickel cobalt system promotes enhanced conductivity as well, if included in small enough amounts. As the nickel concentration in the film increases, less lithium is required to produce a conductivity increase. Lithium containing films also exhibit the same recoverable conductivity behavior when subjected to heat treatment. Electrical property measurements are correlated with vibrational and electron spectroscopy results. Structural nuances are characterized by means of HRTEM. Perturbations to the conductivity are thought to arise from the presence of chemisorbed species such as carbonate and cation partitioning among available sites in the lattice.