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.