A pentacene field-effect transistor with light-programmable threshold voltage

We report the effect of light illumination on the electrical characteristics of pentacene field-effect transistors with a large-bandgap conjugated polymer PFO as the interfacial layer. The nanostructured PFO servers as charge-trapping centers that capture charges injected from the pentacene active layer. When the device is under light illumination, the threshold voltage (Vth) can be modulated by varying positive gate biases such that the operation mode can be switched from the enhancement mode to the depletion mode. This light-programmable feature may motivate the development of this new type of organic memory devices.