Zirconium-aluminum co-doping on solution-processed indium oxide thin film and deceives measured by a novel nondestructive method

Abstract

Solution-processed co-doped indium oxide (In₂O₃) have broad application prospects in the display industry. In this paper, zirconium-aluminium co-doped indium oxide (InxZryAl1-x-yO) thin films and thin film transistors (TFTs) are prepared by the solution method. Doping ratio of Zr-Al is 1:0, 2:1, 1:1, 1:2 and 0:1, respectively, and the total atomic ratio of Zr-Al doping is 10 at.%. A novel nondestructive method, microwave photoconductivity decay (µ-PCD) is used to evaluate the quality of thin films by simply measuring their response under laser irradiation. The result shows that doping Zr-Al can reduce the defects in In₂O₃ thin films effectively. The addition of Zr can effectively reduce oxygen vacancies, and the addition of Al can inhibit the crystallization of In₂O₃ thin films. The optimal InxZryAl1-x-yO thin film with minimum defects is obtained with doping ratio of Zr:Al = 2:1. The roughness of thin films is below 0.37 nm, and possess exceptional transmittance (>95%) in the visible range. The optimized TFT exhibits mobility of 2.3 cm2µV−1µs−1, an on/off current ratio of 2.0 × 104, a threshold voltage of 2.29 V and a subthreshold swing of 1.61 Vµdec−1 with doping ratio of Zr:Al = 2:1.