Developing pinMOS towards dual channel electrical and optical memory

• Applicant: Professor Dr. Stefan Mannsfeld
• Subject Area: Experimental Condensed Matter Physics
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 515090030

Although memories represent by far the largest part of conventional (silicon-based) electronic systems, work on organic memories is severely lagging behind the research efforts regarding OFETs. While many concepts have been proposed, there is currently no consensus on the way forward. Although a lot of these memory concepts are entirely electronic in nature (i.e., they are both written to and read from by electrical means), some application would tremendously benefit from the ability to read and write optically in addition to the purely electrical way of achieving read/write functionality – for example contactless applications similar to “barcode”-scanners that require read and write without direct physical contact or optical sensors that “remember” light exposure. With this proposal we want to study in detail and further develop a novel memory structure that we recently developed. It can be thought of as a cross between a conventional p-i-n diode OLED structure and a MOS capacitor – dubbed as pinMOS in here. In preliminary experiments, we were already able to observe a distinct memory window and electrical reading and writing of memory states. One important advantage of this technology over others also lies in its foundation in well-established OLED fabrication techniques and the resulting easy integration with OLEDs, i.e. all such scenarios in which OLEDs and memory should be combined. While the initial results are highly promising – not only due to the simplicity of the device compared to FLASH-type floating gate device structures, but also due to its high reproducibility, state stability, and strong indications for a multibit storage capability– the memory qualities of this device need to be further developed which in turn requires us to better understand the device principle and physics. For this, the pinMOS device needs to be studied in much more detail, and its layer structure and properties such as doping concentrations and layer thicknesses need to be optimized for improved memory performance, i.e. increased spread of states. Another major goal is to develop this device into a fully electro-optical memory device. Due to the fact that the device contains a p-i-n junction, one of the memory states can currently already be detected by a brief visible light emission. Extending this to writing and erasing by light can be achieved by 1) replacing the intrinsic device layer with a light harvesting donor-acceptor structure and 2) substituting the oxide for a wide-band gap organic material. Achieving this will enable us to demonstrate the first organic memory device that can be fully yet independently accessed and controlled electrically and optically.

• DFG Programme: Research Grants