Nature-Inspired Capillary-Driven Welding Process for Boosting Metal-Oxide Nanofiber Electronics

Abstract

Recently, semiconducting nanofiber networks (NFNs) have been considered as one of the most promising platforms for large-area and low-cost electronics applications. However, the high contact resistance among stacking nanofibers remained to be a major challenge, leading to poor device performance and parasitic energy consumption. In this report, a controllable welding technique for NFNs was successfully demonstrated via a bioinspired capillary-driven process. The interfiber connections were well-achieved via a cooperative concept, combining localized capillary condensation and curvature-induced surface diffusion. With the improvements of the interfiber connections, the welded NFNs exhibited enhanced mechanical property and high electrical performance. The field-effect transistors (FETs) based on the welded Hf-doped InO (InHfO) NFNs were demonstrated for the first time. Meanwhile, the mechanisms involved in the grain-boundary modulation for polycrystalline metal-oxide nanofibers were discussed. When the high-k ZrO dielectric thin films were integrated into the FETs, the field-effect mobility and operating voltage were further improved to be 25 cm V s and 3 V, respectively. This is one of the best device performances among the reported nanofibers-based FETs. These results demonstrated the potencies of the capillary-driven welding process and grain-boundary modulation mechanism for metal-oxide NFNs, which could be applicable for high-performance, large-scale, and low-power functional electronics.

Electrospinning and Electrospun Nanofibers: Methods, Materials, and Applications

“…Using the vapor method, composite nanofibers made of PVP and In 2 O 3 precursor were also welded at the cross-points. 484 Upon calcination, the welded In 2 O 3 nanofiber-based mat showed enhancement in both mechanical property and electrical conductivity. In addition to vapor, diluted solution can be used to weld the nanofibers at their cross-points.…”

Low-Voltage Hf-ZnO Thin Film Transistors With Ag Nanowires Gate Electrode and Their Application in Logic Circuit

“…Also, the Ag NWs exhibit a resistance of 23 ohm/sq., which is comparable to that of metal oxide ceramic electrodes. It means that Ag NWs have great potential of applications in low-resistance transparent conducting electrodes [4], [20], [21]. Figure 1(b) shows the SEM image of Ag NWs.…”

Photothermal Welding, Melting, and Patterned Expansion of Nonwoven Mats of Polymer Nanofibers for Biomedical and Printing Applications

“…Typical methods for welding the nanofibers involve thermal annealing, chemical cross‐linking, and solvent or vapor treatment . These methods have been applied to enhance the mechanical strength of nanofiber mats comprised of various polymers, including poly( ϵ ‐caprolactone) (PCL), poly(lactic‐ co ‐glycolic acid), polyacrylonitrile, polysulfone, and a blend of poly(vinyl pyrrolidone) and In 2 O 3 precursor, by reinforcing inter‐fiber connection . In general, all these methods lack the feasibility and versatility for patterning (that is, welding the nanofibers in a spatially controlled manner) because all nanofibers in the mat will be welded, or, at least, affected.…”