All-solution-processed nonvolatile flexible nano-floating gate memory devices.

Organic semiconductors have great potential for future electronic applications owing to their inherent flexibility, low cost, light weight and ability to easily cover large areas. However, all of these advantageous material properties can only be harnessed if simple, cheap and low-temperature fabrication processes, which exclude the need for vacuum deposition and are compatible with flexible plastic substrates, are employed. There are a few solution-based techniques such as spin-coating and inkjet printing that meet the above criteria. In this paper, we describe a novel all-solution-processed nonvolatile memory device fabricated on a flexible plastic substrate. The source, drain and gate electrodes were printed using an inkjet printer with a conducting organic solution, while the semiconducting layer was spin-coated with an n-type polymer. The charge-trapping layer was composed of spin-coated reduced graphene oxide (rGO), which was prepared in the form of a solution using Hummer's method. The fabricated device was characterized in order to confirm the memory characteristics. Device parameters such as threshold voltage shift, retention/endurance characteristics, mechanical robustness and reliability upon bending were also analyzed.