Electrospinning-Driven Binary Oxide Nanofiber Networks with Tunable Amorphous Microstructure for Booming Transistors and Circuits Operation

Although In₂O₃ nanofibers (NFs) are regarded as one of the active channel materials for next-generation, low-cost thin-film transistors (TFTs), these NFs-based devices still suffer from the degraded carrier mobility and operational instability, limiting the ability of such devices to replace current polycrystalline silicon technologies. Here, it is shown that nanofiber channel transistors with high electron mobility and operational stability can be achieved by selectively doping Zn element into electrospun In₂O₃ NFs. By precisely manipulating the doping level during NFs fabrication, their crystallinity, surface morphology, and corresponding device performance can be regulated reliably for enhanced transistor performances. It has been detected that InZnO/SiO₂ TFTs with an optimized Zn doping concentration of 50% have demonstrated the high field-effect mobility (µ_FE) of 6.38 cm² V⁻¹ s⁻¹, the larger I_ON/I_OFF of 4.12 × 10⁷ and operation in the energy-efficient enhancement-mode. Low frequency noise (LFN) measurements have displayed that the scattering and defects inside the NFs are effectively suppressed by the particular microstructure. When integrating ALD-derived Al₂O₃ films as the gate dielectric into TFTs devices, their electron mobility and I_ON/I_OFF can be further improved to 37.82 cm² V⁻¹ s⁻¹ and 2.92 × 10⁸, respectively. To demonstrate the potential toward more complex logic applications, a low voltage resistor-loaded unipolar inverter is built by using InZnO/Al₂O₃ TFT, exhibiting a high gain of 20.95 and full swing characteristics. These optimized parameters have demonstrated the significant advance of this electrospinning technique toward practical applications for high performance and large-scale electronics.