Regensburg 1998 – scientific programme
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DS: Dünne Schichten
DS 24: Postersitzung
DS 24.12: Poster
Thursday, March 26, 1998, 15:00–19:00, PF A
Electrical Conductivity in Ion Implanted TiO2-Single Crystal — •R. Fromknecht1, O. Meyer1, I. Khubeis2, S. Massing1, R.C. da Silva3, E. Alves3, and L.M. Redondo3 — 1Forschungszentrum Karlsruhe, INFP, Postfach 3640, D-76021 Karlsruhe — 2Department of Physics, University of Jordan, Amman, Jordan — 3Dep. Fisica, ITN-E.N.10, 2685 Sacavem, Portugal
Single crystals of TiO2 (rutile) were implanted at room temperature with W, Ar and Xe ions, applying fluences between 1014/cm2 and 1017/cm2. The lattice site location together with ion range and damage distribution was measured with Rutherford Backscattering and Channeling (RBS-C). The electrical conductivity increased continuously with W-ion dose and reached a saturation value of about 3·10−3 Ω −1 (corresponding to 50 Ω −1cm−1) at doses of 1017 W/cm2, where the samples are amorphous. Annealing of these samples lead to a dramatic decrease of the conductivity. At low temperatures the temperature dependence of the as-implanted samples indicate that the carrier transport is due to hopping. Implantation of inert gas ions reveales a quite different behaviour. The conductivity dependence on disorder, produced by Ar implantation, revealed a bell shaped behaviour with a maximum value of about 7·10−5 Ω −1 for the partially damaged rutil phase, while for the amorphous phase a value of 1.3·10−7 Ω −1 was determined. From these results it is concluded that the carrier transport in W-doped samples is due to carrier hopping in an impurity band.