# Electrospun Nanofibers for Integrated Sensing, Storage, and Computing Applications
## 3 Electrospun Nanofibers in Transistors: Computation and Multifunctional Electronics
### Advanced Electrospinning Methods for Transistor Production
Annealing and other treatments represent the primary procedure for easy and direct control, and different annealing temperature, time, and atmosphere have been confirmed to affect the mobility and current ratio of the FET by electrospinning. Water-induced (WI) In\({}_{2}\)O\({}_{3}\) nanofibers with varied annealing dependence were prepared and experiments revealed that annealing temperature (280 \({}^{\circ}\)C, 310 \({}^{\circ}\)C, 350 \({}^{\circ}\)C, 380 \({}^{\circ}\)C) and hold time (0.5 h, 1 h, 1.5 h, etc.) would influence the traps in the bulk channel and/or at the interface between the channel and the dielectric, consequently changing the FETs performance in parallel [76]. Among changing annealing conditions, FET based on WI In\({}_{2}\)O\({}_{3}\) nanofibers annealed at 380 \({}^{\circ}\)C for 1 h exhibited field-effect mobility (\(\mu_{\text{FE}}\)) of 1.53 cm\({}^{2}\) V\({}^{-1}\) s\({}^{-1}\), and an ON/OFF current ratio (\(I_{\text{ON}}\)/\(I_{\text{OFF}}\)) of 8 \(\times\) 10\({}^{4}\) (Figure 11i-l). Similar research on ZnO and SnO\({}_{2}\) transistors has proven the impact of annealing temperature and time on the grain size and continuity of the nanofibers and the consequent electrical performance of the transistors [77; 78]. After fibers are fabricated by electrospinning on the collector, plasma treatment can selectively be applied to enhance the FET performance and stability. Using various ratios of Ar/O\({}_{2}\) gas blends, the effects of plasma surface treatment on electrospun In-Ga-ZnO (IGZO) nanofibers and electrospun FETs were examined systematically [79]. As can be seen in Figure 12, because of the ability of Ar plasma to etch the nanofibers, Ar/O\({}_{2}\) mixed plasma treated IGZO nanofibers showed a further reduction in diameter with an increase in the Ar ratio. In addition, when the O\({}_{2}\) ratio in the Ar/O\({}_{2}\) mixed-gas flow grew, the drain current increased. However, as the Ar ratio in the Ar/O\({}_{2}\) mixed-gas flow increased, the drain current of the nanofiber-based FET was reduced. As a result, the highest performance of FET, which exhibited mobility of 5.32 cm\({}^{2}\) V\({}^{-1}\) s\({}^{-1}\) and an on/off current ratio (\(I_{\text{ON}}\)/\(I_{\text{OFF}}\)) of 4.35 \(\times\) 10\({}^{6}\), was obtained with the maximin O\({}_{2}\) concentration in the Ar/O\({}_{2}\) mixed-gas flow without the Ar gas. In summary, electrospun, nanofiber-based field-effect transistors have gained continuous improvement in performance through the persistent exploration of process factors, mobility, and the on/off current ratio for the current nanofiber transistors to become more competitive in the field of electronic devices based on 1D-nanostructure materials. Figure 12: SEM images of (**a**) as-spun IGZO nanofibers at 5000 times magnifications, (**b**) IGZO nanofibers without plasma treatment, and with Ar/O\({}_{2}\) mixed-plasma treatment under gas flow rates (in sccm) in the ratio of (**c**) 50/0, (**d**) 40/10, (**e**) 25/25, (**f**) 10/40, and (**g**) 0/50. (**h**) The average diameter of the electrospun IGZO nanofibers with plasma treatment at 30,000 times magnifications. Reprinted from Reference [79] Copyright 2020 Springer Nature.