Cu–In–O composite thin films deposited by reactive DC magnetron sputtering

• Published in: Physica. B, Condensed matter Condensed matter, 2011-02, Vol.406 (3), p.516-519
• Main Authors: Ye, Fan, Cai, Xing-Min, Dai, Fu-Ping, Jing, Shou-Yong, Zhang, Dong-Ping, Fan, Ping, Liu, Li-Jun
• Format: Article
• Language: English
• Subjects: Condensed matter; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Copper; Cu–In–O; Deposition; Direct current; Electrical properties; Electrical properties of specific thin films; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Flow rate; Indium oxides; Magnetron sputtering; Optical properties; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of specific thin films; Other inorganic semiconductors; Other semiconductors; Physics; Semiconductors; Sputtering; Thin films; Transmittance
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2010.11.026

Cu–In–O composite thin films were deposited by reactive DC magnetron sputtering at room temperature. The samples were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), UV/vis spectrophotometer, four-probe measurement and Seebeck effect measurement, etc. The samples contain Cu, In and O. The ratios of Cu to In and O to In increase with increase in O 2 flow rates. The ratio of Cu to In is over 1 and this suggests that Cu is in excess. The obtained Cu–In–O thin films are very possibly made of rhombohedral In 2O 3 and monoclinic CuO. Transmittance of the films decreases with increase in O 2 flow rate. The decrease in transmittance results from increase in Cu content in the films. The optical band gap of all the samples is estimated to be 4.1–4.4 eV, which is larger than those of In 2O 3 and CuO. The sheet resistance of the films decreases with increase in O 2 flow rate. Conductivity of the films is a little low, due to the addition of Cu and the poor crystalline quality of the film. The conduction behavior of the films is similar to that of In 2O 3 and the conduction mechanism of Cu–In–O thin films is through O vacancy. ►Cu-In-O composite thin films were fabricated by DC sputtering at room temperature. ►The films are made of rhombohedral In 2O 3 and monoclinic CuO. ►The transmittance depends on the Cu content in the film. ►The direct optical band gap is around 4.1–4.4eV. ►The conducting mechanism is due to oxygen vacancy.