Solution‐Processed Alkaline Lithium Oxide Dielectrics for Applications in n‐ and p‐Type Thin‐Film Transistors.

High‐k alkaline lithium oxide (LiO_x) thin films are fabricated by spin‐coating method. The LiO_x thin films are annealed at different temperatures and characterized by various techniques. An optimized LiO_x dielectric is achieved at an annealing temperature of 300 °C and exhibits wide bandgap of ≈5.5 eV, smooth surface, relatively permittivity of ≈6.7, and low leakage current density. The as‐fabricated LiO_x thin films are integrated, as gate dielectrics, in both n‐channel indium oxide (In₂O₃) and p‐channel cupric oxide (CuO) transistors. The optimized In₂O₃/LiO_x thin‐film transistor (TFT) exhibits high performance and high stability, such as I_on/I_off of 10⁷, electron mobility of 5.69 cm² V⁻¹ s⁻¹, subthreshold swing of 70 mV dec⁻¹, negligible hysteresis, and threshold voltage shift of 0.1 V under bias stress for 1.5 h. Meanwhile, the p‐channel CuO TFT based on LiO_x dielectric shows high I_on/I_off of 10⁵ and hole mobility of 1.72 cm² V⁻¹ s⁻¹. All the electrical performances are achieved at an ultra‐low operating voltage of 2 V. Considering the simple procedure, the moderate annealing temperature, and the low power consumption merits, these outstanding characteristics represent a significant advance toward the development of battery compatible and portable electronics. [ABSTRACT FROM AUTHOR]