Programmable and Erasable Pentacene/Ta2O5 Phototransistor Memory With Improved Retention Time

Integrating the photosensitive and memory properties into one single device, organic phototransistor memory (OPTM) is promising for applications in optoelectrical fields. By optimizing the channel length/width ratio and the resistance of the electrode lead, OPTM performance could be improved effectively. Interestingly, the OPTM showed no obvious memory effect with an electrical programming process, while applied along with light illumination, the photoresponsivity, photocurrent/dark current ratio, and shift of threshold voltage could achieve the highest values, which were 3.59 A W^-1, 1.4 × 10⁴, and 14.4 V, respectively. Notably, the retention time over 1.8 × 10⁵ s was 27 times longer than our previous reports and could ensure the application in nonvolatile memories. Furthermore, the OPTM could be applied in programmable and erasable circuit. It is also potential in flexible device.