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

Abstract

In this work, transparent ZnO thin‐film transistors (TFTs) are fabricated on ITO glass substrate with only solution processes. The active ZnO channels are deposited by spray pyrolysis. The gate dielectric is a spin‐coated high dielectric constant (k) titanium‐silicon oxide (TSO) layer, while the source/drain (S/D) electrodes are patterned by two‐step spray‐printing of silver nanowire (AgNWs)/poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) transparent conductive composite through a shadow mask. The composition and microstructural characteristics of the films, as well as their TFTs performance, are systematically studied as a function of the temperature. The introduction of TSO high k dielectric, with ultraviolet (UV)‐assisted post‐annealing, significantly improves the device performance and achieves a maximum electron mobility (µmax) value as high as 56.2 cm2 V−1 s−1 when measured with thermally‐evaporated Al top electrode. For fully solution‐processed transparent TFTs with low temperature fabricated AgNWs/PEDOT:PSS S/D electrodes, the µmax is calculated to be 9.1 cm2 V−1 s−1 operating at a relatively low voltage of <3 V. The TFTs also show hysteresis‐free electrical characteristics and optical transparency of ≈80% in the visible region of the optical spectrum.

High-Performance Fully Solution-Processed Oxide Thin-Film Transistors via Photo-Assisted Role Tuning of InZnO

“…The achieved μ in this work is the highest value among the reported fully solution-processed oxide TFTs, as illustrated in Table S1 (Supporting Information). ,− Moreover, the V on around 0 V and small SS values are comparable to vacuum-processed oxide TFTs. Moreover, this treatment combination resulted in the highest yield and most precise calculated characteristics among the fully solution-processed a -IZO TFTs subjected to a combination of UV and ELA.…”

“…Nevertheless, there have been few attempts on fabricating oxide TFTs, which are fully based on solution-processed layers. ,− Although these studies are noteworthy for successfully integrating functional solution-based layers for oxide TFTs, the devices demonstrated poor performance with mobility ( μ ), typically <5 cm 2 V –1 s –1 ,− , with very few cases exhibiting μ < 10 cm 2 V –1 s –1 . , Moreover, these reports involve complicated fabrication methods requiring diverse materials with various deposition and patterning steps as well as high fabrication temperature (<500 °C) or lengthy annealing processes. ,, Here, we report a low-temperature approach for fully solution-processed oxide TFT fabrication using a -IZO for the channel and electrode materials and fluorinated-polysilsesquioxane (F-PSQ) for the gate insulator. The maximum process temperature employed during film deposition steps was 300 °C, and the required temperature during photo-assisted treatments was only 115 °C.…”

“…33,35 Moreover, these reports involve complicated fabrication methods requiring diverse materials with various deposition and patterning steps as well as high fabrication temperature (<500 °C) or lengthy annealing processes. 5,31,35 Here, we report a low-temperature approach for fully solution-processed oxide TFT fabrication using a-IZO for the channel and electrode materials and fluorinated-polysilsesquioxane (F-PSQ) for the gate insulator. The maximum process temperature employed during film deposition steps was 300 °C, and the required temperature during photo-assisted treatments was only 115 °C.…”

Highly Transparent and Surface-Plasmon-Enhanced Visible-Photodetector Based on Zinc Oxide Thin-Film Transistors with Heterojunction Structure

“…The TFTs were indeed highly transparent (transmission of ~70% in the visible spectrum) and showed excellent electrical characteristics including an I ON /I OFF ratio of approximately 10 4 through the spray pyrolysis to deposit the active ZnO channel layer. These results represent significant achievements toward low cost and low energy consumption transparent oxide TFTs based on simple solution-based processes [24,37]. However, the spray-deposited film still exhibited high roughness of the micro-grade film as compared with the spin-coated film, and a high temperature manufacturing process >400 °C was involved.…”

P‐11: High Performance All‐Solution Processed InZnO Thin‐Film Transistors via Photo‐Functionalization at Varying Fluence and Annealing Environment

“…To date, there have been few reports on all-solution-processed oxide TFT fabrication. However, key issues remain such as hightemperature fabrication (>400˚C), requirement of diverse materials and numerous patterning steps, and μ <10 cm 2 V -1 s -1 [6,7]. Here, we demonstrate high-performance all-solution processed IZO TFTs with a maximum fabrication temperature of 300˚C.…”