Organic non-volatile memory based on pentacene/tris(8-hydroxy quinoline) aluminum heterojunction transistor

Non-volatile heterojunction transistor memory was fabricated by successively depositing pentacene/tris(8-hydroxy quinoline) aluminum(Alq₃) layers. In this specified configuration, pentacene functioned as the active layer between the source and drain of field-effect transistor memory, and Alq₃ was adopted as the charge-trapping layer. Operation of non-volatile memory was implemented by an electrical writing and light illumination erasing procedure. Band bending between pentacene and Alq₃ due to the formation of a type II heterojunction prohibited back-injection of trapped charges, which demonstrated hysteresis for the transfer characteristics. The specified heterojunction structure (without a tunneling layer) enabled carriers to facilely transport between the active layer and charge trapping layer. Therefore, a large memory window (40.3 V, for a programming voltage of −80 V) and fast writing speed of less than 1 μs were demonstrated; in addition, the 1-bit non-volatile memory device showed a moderate retention time of more than 2 years. The large memory window, fast writing speed, and long retention time can potentially enable practical applications of non-volatile memory.