Weak localization and size effects in thin In2O3 films prepared by autowave oxidation

Abstract

The negative magnetoresistance of thin In2O3 films, obtained by an autowave oxidation reaction, was detected within a temperature range of 4.2–80K. The magnetoresistance was –1.35% at a temperature of 4.2K and an external magnetic field of 1T. A weak localization theory was used to explain the negative magnetoresistance and to determine the phase-coherence length in a temperature range of 4.2–80K. The phase-coherence length was found to oscillate as the temperatures increased to around 30K. From the maximum and minimum values of the oscillation of the phase-coherence length, it was suggested that the In2O3 film has two structure characteristic parameters. Transmission electron microscopy showed the structure of the thin In2O3 film to have structural features of a «crystal phase – amorphous phase». It was found that the crystalline phase characteristic size was consistent with the maximum phase-coherence length and the amorphous phase characteristic size was consistent with the minimum phase-coherence length. It has been suggested that the temperature measurements of the magnetoresistance and the theory of weak localization can be used to evaluate the structural features of nanocomposite or nanostructured thin films.