Microwave-assisted calcination of electrospun indium-gallium-zinc oxide nanofibers for high-performance field-effect transistors

The effects of microwave-assisted calcination of electrospun In-Ga-Zn-O (IGZO) nanofibers intended for electronic devices are unclear. To this end, a systematic study was conducted on the effects of microwave-assisted calcination on the microstructure and optical and mechanical properties of electrospun IGZO nanofibers used in high-performance field-effect transistors (FETs). To clarify the role of microwave annealing (MWA) on the characteristics of the electrospun nanofibers, calcination was carried out using two techniques: MWA and conventional thermal annealing (CTA). The morphological differences between IGZO nanofibers calcined using the two techniques were analyzed by scanning electron microscopy (SEM); the diameter of nanofibers was significantly reduced through MWA as compared to CTA. After calcination, the optical transmittance in the visible region was slightly improved, with the MWA-calcined nanofibers exhibiting a higher transmittance than the CTA-calcined nanofibers. Scratch test results showed that the calcination improved the adhesion strength of the nanofibers to the SiO2 substrate; MWA was more effective in improving the mechanical properties than CTA. Furthermore, the effects of MWA calcination on the electrical properties of FETs fabricated using the electrospun IGZO nanofibers were investigated. The MWA-calcined devices showed better electrical characteristics and reliability than the CTA-calcined devices for IGZO nanofiber FETs.