Tungsten-doped In2O3 transparent conductive films with high transmittance in near-infrared region

Polycrystalline tungsten-doped In2O3 (IWO) thin films prepared by dc reactive magnetron sputtering exhibit the high transparency in near-infrared region. The optoelectrical properties of the films were investigated in terms of different oxygen contents. The average transmittance of the films at oxygen content from 3.3% to 8.3% is approximately 90% in near-infrared region from 700 to 2500 nm, and about 94% in visible region from 400 to 700 nm. The high transparency is ascribed to the low carrier concentration of less than 3.8×1020 cm−3 of IWO films. The as-deposited IWO films with minimum resistivity of 3.1×10−4 Ω cm were obtained at 6.7% oxygen content. Carrier mobility reaches its highest value of 67 cm2 V−1 s−1. Indium tin oxide (ITO) thin film prepared under the same sputtering condition shows a similar resistivity of 3.2×10−4 Ω cm but a much lower mobility of 21 cm2 V−1 s−1 and high carrier concentration of 9.4×1020 cm−3, with the average transmittance of about 48% in near-infrared region and about 92% in visible region.