High-Performance Thin Film Transistor with an Neodymium-Doped Indium Zinc Oxide/Al ₂O ₃ Nanolaminate Structure Processed at Room Temperature

Abstract

In this work, a high-performance thin film transistor with an neodymium-doped indium zinc oxide (Nd:IZO) semiconductor via a room temperature approach and adopting the Nd:IZO/Al ₂O ₃ nanolaminate structure was investigated. The effects of the ultrathin Al ₂O ₃ layer and the thickness of Nd:IZO layer in the nanolaminate structure on the improvement of electrical performance and stability of thin film transistors (TFTs) were systematically studied. Besides the carrier movement confined along the near-channel region, driven by the Al ₂O ₃ layer under an electrical field, the high performance of the TFT is also attributed to the high quality of the 8-nm-thick Nd:IZO layer and the corresponding optimal Nd:IZO/Al ₂O ₃ interface, which reduce the scattering effect and charge trapping with strong M–O bonds in bulk and the back-channel surface of Nd:IZO, according to the X-ray reflectivity (XRR), X-ray photoelectron spectroscopy (XPS), and micro-wave photo conductivity decay (μ-PCD) results. As a result, the Nd:IZO/Al ₂O ₃ TFT exhibits an outstanding performance, with a high μ _sat of 32.7 cm ²·V ⁻¹·s ⁻¹, an I _on/I _off of 1.9 × 10 ⁸, and a low subthreshold swing ( SS) value of 0.33 V·dec ⁻¹, which shows great potential for the room temperature fabrication of TFTs in high-resolution or high-frame-rate displays by a scalable, simple, and feasible approach.