Fully Solution-Processed Low-Voltage Driven Transparent Oxide Thin Film Transistors

摘要

In this work, transparent ZnO thin-film transistors (TFTs) are fabricated onITO glass substrate with only solution processes. The active ZnO channelsare deposited by spray pyrolysis. The gate dielectric is a spin-coated highdielectric constant (k) titanium-silicon oxide (TSO) layer, while the source/drain (S/D) electrodes are patterned by two-step spray-printing of silvernanowire (AgNWs)/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS) transparent conductive composite through a shadow mask. Thecomposition and microstructural characteristics of the films, as well as theirTFTs performance, are systematically studied as a function of the temperature.The introduction of TSO high k dielectric, with ultraviolet (UV)-assistedpost-annealing, significantly improves the device performance and achieves amaximum electron mobility (μ_(mmax)) value as high as 56.2 cm~2 V~(-1) s~(-1) whenmeasured with thermally-evaporated Al top electrode. For fully solutionprocessedtransparent TFTs with low temperature fabricated AgNWs/PEDOT:PSS S/D electrodes, the mmax is calculated to be 9.1 cm~2 V~(-1) s~(-1) operating ata relatively low voltage of <3 V. The TFTs also show hysteresis-free electricalcharacteristics and optical transparency of ≈80% in the visible region of theoptical spectrum.