In this work, copper nanowires (NWs) and Cu nanoparticles (NPs) were employed to increase the reliability of a printed electrode pattern under mechanical bending fatigue. The fabricated Cu NW/NP inks with different weight fractions of Cu NWs were printed on a polyimide substrate and flash light-sintered within a few milliseconds at room temperature under ambient conditions. Then, 1000 cycles of outer and inner bending fatigue tests were performed using a lab-made fatigue tester. The flash light-sintered Cu NW/NP ink film with 5 wt % Cu NWs prepared under the flash light-sintering conditions (12.5 J·cm–2 irradiation energy, 10 ms pulse duration, and one pulse) showed a lower resistivity (22.77 μΩ·cm) than those of the only Cu NPs and Cu NWs ink (94.01 μΩ·cm and 104.15 μΩ·cm, respectively). In addition, the resistance change (ΔR·R0(–1)) of the 5 wt % Cu NWs Cu NW/NP film was greatly enhanced to 4.19 compared to the 92.75 of the Cu NPs film obtained under mechanical fatigue conditions over 1000 cycles and an outer bending radius of 7 mm. These results were obtained by the densification and enhanced mechanical flexibility of flash light-sintered Cu NW/NP network, which resulted in prevention of crack initiation and propagation. To characterize the Cu NW/NP ink film, X-ray diffraction and scanning electron microscopy were used.

In this study, an intense pulsed light (IPL) process for annealing an indium–gallium–zinc–oxide (IGZO) semiconductor was conducted via flash white light combined with near-infrared (NIR) and deep-ultraviolet (DUV) drying to form a thin-film transistor (TFT). The IGZO thin-film semiconductor was fabricated using a solution-based process on a doped-silicon wafer covered with silicon dioxide. In order to optimize the IPL irradiation condition for the annealing process, the flash white light irradiation energy was varied from 70 to 130 J/cm2. Drying by NIR and DUV irradiation was employed and optimized to improve the performance of the TFT during IPL annealing. A TFT with a bottom-gate and top-contact structure was formed by depositing an aluminum electrode on the source and drain on the IPL-annealed IGZO. The electrical transfer characteristic of the TFT was measured using a parameter analyzer. The field effect mobility of the saturation regime and on/off current ratio were evaluated. Changes of the metal–oxide bonds in the IGZO thin film were analyzed using X-ray photoelectron spectroscopy to verify the effect of NIR and DUV drying and IPL annealing. Also, the distributions of the carrier concentration on the IPL-annealed IGZO were measured through a hall-effect system to deeply investigate the transition of the electrical characteristic of the TFT. From the results, it was found that the bond between oxygen and the gallium compound was activated via DUV irradiation. The NIR- and DUV-assisted IPL-annealed IGZO-based TFT showed highly enhanced electrical performance with a 7.7 cm2/V·s mobility and a 3 × 106 on/off ratio.

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