An organic ambipolar charge trapping non-volatile memory device based on double heterojunctions

•Memory device based on double heterojunctions enables fully-electrical operation.•The C60/Pentacene sole heterojunction shows large built-in field.•The double heterojunctions suppress the large built-in field. An organic ambipolar charge trapping non-volatile memory device is proposed based on tris(8-hydroxy quinoline) aluminum(Alq3)/ fullerene(C60)/pentacene double heterojunctions. The double heterojunctions were analyzed and compared with the sole heterojunction. Even though the Alq3/pentacene sole heterojunction shows a negative threshold voltage shift for programming under negative biasing, light illumination is required to efficiently erase. In contrast, for C60/pentacene sole heterojunction, the negative shift of threshold voltage is observed even with a positive erasing voltage. By combining the two trapping layers, a large memory window with fully-electrical programming and erasing is obtained. The efficient programming and erasing of the double heterojunctions structure are analyzed, sufficient electrons can be injected that enables the electrical erasing, and the negative shift of the threshold voltage under positive erasing voltage for the C60/pentacene structure is suppressed due to the suppression of the large built-in potential for the sole heterojunction, which can be verified by a large positive shift for the pentacene/C60/pentacene double heterojunctions.