Sb-related defects in Sb-doped ZnO thin film grown by pulsed laser deposition

Sb-doped ZnO films were fabricated on c-plane sapphire using the pulsed laser deposition method and characterized by Hall effect measurement, X-ray photoelectron spectroscopy, X-ray diffraction, photoluminescence, and positron annihilation spectroscopy. Systematic studies on the growth conditions with different Sb composition, oxygen pressure, and post-growth annealing were conducted. If the Sb doping concentration is lower than the threshold similar to 8 x 10(20) cm(-3), the as-grown films grown with an appropriate oxygen pressure could be n similar to 4 x 10(20) cm(-3). The shallow donor was attributed to the SbZn related defect. Annealing these samples led to the formation of the Sb-Zn-2V(Zn) shallow acceptor which subsequently compensated for the free carrier. For samples with Sb concentration exceeding the threshold, the yielded as-grown samples were highly resistive. Xray diffraction results showed that the Sb dopant occupied the O site rather than the Zn site as the Sb doping exceeded the threshold, whereas the SbO related deep acceptor was responsible for the high resistivity of the samples. Published by AIP Publishing.