Effect of UV-assisted low-temperature annealing on electrical performance of Zn-Sn-O nanofiber-based field effect transistors

Low-temperature fabrication process of thin film transistors is essential for the flexible electronics using plastic substrates. We demonstrated the Zn-Sn-O (ZTO) nanofiber-based field effect transistors (FETs) which were fabricated at low temperature where the plastic substrates can be sustained. The nanofibers (NFs) were prepared by an electrospinning method incorporated with low-temperature decomposable nitrocellulose polymer and ultra-violet (UV) exposure. UV irradiation was applied under varying conditions, and all treated devices exhibited better electrical characteristics than their unirradiated counterparts. The synergetic effect of thermal annealing and photon energy from UV irradiation demonstrated improved adhesion between adjacent nanofibers and the nanofiber/dielectric interface, enhancing the electrical performance of NF-based FETs. The pre-exposure FET (Pre-F) showed the optimal electrical performance with an on/off current ratio exceeding 10⁶, a low threshold voltage of −0.1 V, decent saturation mobility, and density of interface traps of 6.3 × 10¹² cm⁻². This low-temperature-fabricated ZTO NF-FET can be compatible with flexible polymer substrates, providing a platform for future applications in flexible electronics.