Flexible InGaZnO Thin-Film Transistors With Gelatin Gate Dielectric for Nonvolatile Memory

Recently, the use of natural materials in device fabrication has become a significant trend in advancing eco-friendly and sustainable electronics, to achieve technologies with low carbon footprints and yet reliable functionality. This work demonstrates utilization of gelatin, a natural protein, as a gate dielectric, in combination with indium gallium zinc oxide (InGaZnO) semiconductor, to fabricate top-gated flexible thin-film transistors (TFTs). More specifically, these devices exhibit nonvolatile memory characteristics for 10 V operation upon application of a voltage sweep of ±10 V, with a maximum memory window (MW) of $\approx 12$ V and repetition for 100 continuous scans. Moreover, consistent static retention was obtained with a current on-off ratio of ${\gt }10^{5}$ for 3 h. The hygroscopic nature of gelatin enabled these devices to demonstrate reliable response as humidity sensor upon exposure to a humidity pulse (in the range between 42% and 90% relative humidity). In addition, TFTs demonstrated functionality during bending condition (down to 7 mm bending radius) with 8 months-long shelf-life.