Effect of isothermal annealing on electrical and optical properties of Al-doped ZnO films


Effect of isothermal annealing on electrical and optical properties of Al-doped ZnO films

Vinnichenko, M.; Rogozin, A.; Shevchenko, N.; Kolitsch, A.; Möller, W.

The aim of present work is to investigate mechanisms of Al incorporation and its effects on electrical and optical properties of ZnO
films. Highly c-axis textured polycrystalline thin films of insulating ZnO were implanted by 110 keV Al+ ions and then annealed at 520 °C. The films were characterized by Hall effect, four-point probe, spectroscopic ellipsometry and x-ray diffraction techniques. The films are
nanocrystalline in as-implanted state. Their dielectric function shows broadened features near the band gap energy and increased, compared
to unimplanted films, absorption in the near IR and visible spectral range. If the implantation dose is below 2x10^16 cm−2, the free electron
density, Ne, increases after annealing and the film resistivity decreases monotonously during annealing. If the dose is above 2x10^16 cm−2, Ne
decreases after annealing while film resistivity reaches minimum and then increases during the treatment. The annealing decreases optical
absorption in the near IR and visible and improves film crystallinity. The behavior of the film electrical properties may be explained by the
interplay between oxygen vacancies formation and Al donor activation.

Keywords: Al-doped ZnO; ion implantation; reactive pulsed magnetron sputtering; spectroscopic ellipsometry

  • Lecture (Conference)
    72. Jahrestagung der DPG und DPG Frühjahrstagung des Arbeitskreises Festkörperphysik mit anderen Fachverbänden und den Arbeitskreisen der DPG, 25.-29.02.2008, Berlin, Germany

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Publ.-Id: 11105