Organic nonvolatile memory transistors with self-doped polymer energy well structures

Developing organic nonvolatile memory devices with a writing/reading/erasing logic function in actual array structures is extremely important for realizing low-cost lightweight/flexible plastic electronic systems. Here, we demonstrate that organic field-effect transistors (OFETs) with a polymer energy well structure (PEW-OFET) exhibit excellent nonvolatile memory performances. The PEW structure is created by sandwiching a self-doped poly(o-anthranilic acid) (SD-PARA) nanolayer (high dielectric constant, k=14) between two low-dielectric polymer layers (k=2–4). The primary idea behind this concept is the rapid storage and retrieval of charge carriers in the PEW layer during operation due to the high k feature of the SD-PARA nanolayer, which aids the rapid transport of charge carriers inside, whereas the stored charges are safely trapped due to the two low k layers. The results indicate that the PEW-OFET memory devices exhibit outstanding retention characteristics upon continuous reading up to 2000 s after writing, whereas their excellent writing/reading/erasing/reading cyclability is demonstrated in a test with >3000 cycles. Therefore, the present simple yet cost-effective PEW-OFET concept is expected to significantly contribute to the development of low-cost plastic memory array devices because all processes can be inexpensively performed at low temperatures and additional logic transistors are unnecessary. Organic electronics play an increasingly important role in devices such as mobile phone displays or flexible electronic circuits. To complement such organic electronic devices, Youngkyoo Kim, Moonhor Ree and colleagues from Kyungpook National University and Pohang University of Science and Technology in Korea have now developed a fully organic non-volatile memory device capable of storing information over a long period of time. The device is composed of a thin layer of a polymer that readily sustains an electric field, sandwiched by layers of semiconducting polymers that resist the formation of an electric field. This combination effectively traps charges in the middle layer allowing the long term storage of information. Data can be written into the devices memory by applying an external electrical voltage and the authors demonstrate that the device retains its integrity over more than 3,000 read and write cycles. The simple construction and good performance profile of this system holds out promise for its use as a practical memory element for other organic electronics devices. Organic field-effect transistors with a self-doped (SD) polyaniline charge-trapping energy well structure exhibit outstanding nonvolatile memory characteristics. The charges generated by the field-effect operation are effectively stored in the SD poly(o-anthranilic acid) charge-trapping energy well layer so that the present memory transistor performs excellent data writing–reading–erasing functions with highly stable data retention characteristics.