Optical Programming/Electrical Erasing Memory Device Based on Low-Voltage Organic Thin-Film Transistor

We demonstrated a low-operation-voltage pentacene organic thin-film transistor (OTFT) with an ultrathin polymer poly(methyl methacrylate co glycidyl methacrylate) as the gate dielectric layer. Under illumination, the threshold voltage (VT) continuously shifted positively, and the operation current (I_DS) successively increased with the applied circular gate voltage (VG). After the light switchoff, both VT and I_DS decayed to a metastable state and remained for a long time before decaying back to the initial value. This OTFT has a potential application in a photodetector with nonvolatile memory effect or in a memory by optical programming (P) and electrical erasing (E). The I_DS was turned into a large value (one state) after P by a positive VG pulse under illumination and quickly returned to a small initial value (zero state) after E by a negative VG pulse. The present OTFT fabricated by a simple fabrication process exhibits a good practical foreground due to the low operation voltage and the good repeatability.