Page 179 - Read Online

Jeon et al. Soft Sci. 2025, 5, 1 https://dx.doi.org/10.20517/ss.2024.35 Page 9 of 39

Figure 3. High-performance flexible MO TFTs employing multiple channel layers. (A) Photograph, schematic diagram, and transfer
characteristics of TiO /IGZO TFT on PI before and after bending. Reproduced with permission [82] , Copyright 2015, Elsevier; (B)
x
Schematics of MO TFTs employing heterojunction and QSL channel layer, transfer properties of different oxide-based channel layers
including ZnO and In O and Arrhenius plots of saturation mobility depend on temperature for ZnO, In O , heterojunction, and OSLs-
2
3
2
3
based TFTs measured at V = 80 V and V = 100 V. Reproduced with permission [125] , Copyright 2015, Wiley-VCH; (C) Schematics and
G
D
transfer characteristics of 3C-TFTs and IZI-TFTs. Reproduced with permission [99] , Copyright 2022, Wiley-VCH; (D) Transfer
characteristics of D4 Ga O /ZnO-stack TFTs and flexible Ga O /ZnO TFT with different folding cycles (up to 100k) and threshold
3
2
2
3
voltage shift of flexible Ga O /ZnO TFT with a different folding cycle; the insets show schematic diagram for Ga O and ZnO films on
2
3
3
2
ZrO and the photograph of a foldable device. Reproduced with permission [98] , Copyright 2022, American Chemical Society. MO: Metal
x
oxide; TFTs: thin-film transistors; IGZO: indium gallium zinc oxide; PI: polyimide; QSL: quasi-superlattice; 3C-TFTs: triple-coated indium
oxide; IZI-TFTs: indium oxide/zinc oxide/indium oxide.
quasi-superlattices (QSLs) composed of alternating layers of In O , gallium oxide (Ga O ), and ZnO, created
3
3
2
2
through sequential spin casting at low temperatures (180-200 °C). The optimized QSL transistors
-1 -1
2
demonstrate electron mobilities of 25-45 cm ·V ·s , which is about ten times higher than that of single oxide
2
-1 -1
devices (2-5 cm ·V ·s ). The enhanced performance is attributed to quasi-2D electron gas-like systems at