Bio-Cellulose Substrate for Fabricating Fully Biodegradable Resistive Random Access Devices

Organic resistive random access memory (RRAM) has high potential in the nonvolatile memory field for next-generation green electronics. In general, RRAM devices are usually fabricated on substrates, for example, glass and plastic. In the present study, an Al/gelatin/Ag sandwiched structure on a bio-cellulose (BC) film is demonstrated, whose texture is flexible, ductile, and can be adapted to uneven surfaces. The BC film could be degraded completely in soil in only 5 days. In addition, the gelatin dielectric layer and the BC film substrate are non-toxic and environmentally friendly, realizing a skin-inspired and fully biodegradable device. This Al/gelatin/Ag/BC device shows a high on/off current ratio (>104), low operation voltage (<3 V), and good uniformity at room temperature without obviously aging by which it can still retain its ability. Moreover, this device also withstands the simulation of the effects on temperature and perspiration of human skin, investigated by measuring the electrical characteristics after attaching it onto pigskin. The results show that the device can be operated repeatedly, and the high on/off current ratio (close to 104) is still retained. The outstanding performances prove its feasibility as a skin-attachable wearable device. The demonstration implies that the skin-inspired biodegradable device is a forward-looking development and can be applied to the physiological evaluation and daily recording of wearable devices.