Mo-and Mn-doped VO 2 thin films have been grown on c-cut sapphire substrates by the magnetron co-sputtering technique. The effects of Mo and Mn doping on the structure and metal-insulator transition of the doped VO 2 thin films were studied. An enlargement of the out-of-plane lattice constant of the film caused by Mo doping was observed. As expected, the transition temperature (T MI) is reduced by Mo doping. However, the valence of the Mo ions doped in the VO 2 films is determined by X-ray photoelectron spectroscopy to be 6+ on the surface, but 4+ and 3+ in the bulk part of the films. The reduction in T MI observed in this study is attributed to the variation in the band structure resulting from the incorporation of Mo 4+ into the VO 2 lattice. The optical transmission is remarkably enhanced by low-concentration Mo doping and then monotonically decreases with increasing Mo content. On the other hand, the out-of-plane lattice constant and T MI are not affected by Mn doping. The transmission is enhanced and then monotonically increases with increasing Mn concentration. The thermochromism of doped films is suppressed by Mo and Mn doping.

Amorphous InGaZnO4 (a-IGZO) films doped with various concentrations of Mn have been fabricated by using pulsed-laser deposition technique. Optical, electrical, and magnetic properties of the prepared Mn-doped a-IGZO films were investigated. The resistivity, carrier concentration, and carrier mobility of the a-IGZO films were found to be, respectively, increased, decreased, and enhanced by Mn doping. Moreover, the optical transmission is slightly increased in the visible range and the optical band gaps are not affected in the Mn-doped films. Room-temperature ferromagnetism has been observed in the field-dependent magnetization measurements.

We prepared La 2=3 Ca 1=3 MnO 3Ày films with various oxygen contents on SrTiO 3 substrates and measured the temperaturedependent resistivity of the manganite films under tensile stress due to the lattice mismatch between manganites and singlecrystal substrates. The effect of oxygen vacancies on the transport properties of the films was investigated. The experimental results reveal that the dependence of temperature on the resistivity of fully oxygenated films can be attributed to the adiabatic small-polaron conduction and unconventional one-magnon scattering at temperatures above and far below the insulator-metal (I-M) transition temperature, respectively. However, for highly oxygen-deficient films, the temperature-dependent resistivity can be ascribed to Mott's variable-range-hopping and small polaron metallic conduction at temperatures above and far below the I-M transition temperature, respectively.

We report the fabrication of textured VO2− x films on c-cut sapphire substrates by postdeposition annealing of V2O3 films prepared by RF magnetron sputtering using V2O3 as the target. Although the prepared VO2− x films are expected to be oxygen-deficient, overoxidation on the film surface was revealed by X-ray photoelectron spectroscopy. The metal–insulator transition (MIT) characteristics of the VO2− x films were investigated. MIT parameters including the transition temperature, transition sharpness, and hysteresis width of the VO2− x films were manipulated by varying the oxygen pressure during postdeposition annealing. The suppression of optical transmittance in the near-infrared region was observed by increasing the temperature through the MIT.

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