Engineering high-k LaxZr1−xOy dielectrics for high-performance fully-solution-processed transparent transistors

Summary form only given. Metal oxide thin-film transistors based on high-k dielectrics (ZrO_x, HfO_x, Al₂O_x) are a promising technology with attractive performance (μ_eff ~ 10 -100 cm²/Vs, On/Off > 10⁷) and high transparency (80 - 90%). Solution-processed routes to oxide TFTs can potentially leverage printing technologies to enhance material utilization and throughput. However, realizing the true benefits of solution-processed oxide TFTs requires integrating dielectrics, semiconductors, and conductors that are printable and transparent. To date, there have been few reports of fully solution-processed, transparent oxide TFTs. Full oxide integration is difficult because solution-processed transparent conducting oxides (TCO), such as ITO (Tin-doped indium oxide) and ATO (Antimony-doped tin oxide), reach acceptable conductivity (100 - 1000 S/cm) only after annealing at 400°C - 500°C, while promising high-k dielectrics, such as ZrO_x, crystallize at these temperatures, resulting in high leakage and poor reliability. Here, we demonstrate that doping zirconia with lanthanum can reduce leakage and improve low-frequency dispersion, resulting in a robust dielectric for printed oxide TFTs. We apply these dielectrics in ZnO TFTs, achieving mobilities > 6 cm²/Vs and On/Off ratios > 10⁶.