High-performance multiple-doped In2O3 transparent conductive oxide films in near-infrared light region

Abstract

High-quality W, Mo, Ti, Zr, and Ga-doped indium oxide (multiple-doped In2O3) films are deposited at room temperature by direct current magnetron sputtering process under different oxygen proportion, with 200 °C annealing. A maximum Hall mobility of 71.6 cm2 V−1 s−1 is obtained at a middle oxygen proportion of 2%, thanks to the reduction of impurity scattering center, which is nearly three times higher than an ITO film of 23.6 cm2 V−1 s−1. The multiple-doped In2O3 films showed a remarkable 30% improvement of the optical transmittance (>80%) in the near-infrared (NIR) region compared to the ITO film (about 60%), which is mainly attributed to the decrement of free carrier absorption due to low carrier concentration (<2 × 1020 cm−3), an order magnitude lower than the ITO film (1.56 × 1021 cm−3). Additionally, x-ray diffraction results confirm that the films have a polycrystalline structure with preferential orientation growth in the <100> direction. In the NIR region, the multiple-doped In2O3 films have a superior figure of merit of 5.02 × 10−3 Ω−1, which is an order magnitude higher than the ITO film (5.31 × 10−4 Ω−1). This work reports a new In2O3-based material with both high electrical and optical performance, which is suitable for the application of advanced optoelectronic devices.