By integrating a light-emitting electrochemical cell with a resistive random-access memory that are both based on perovskite, the researchers reported that they achieved parallel and synchronous reading of data both electrically and optically in a "light-emitting memory." The development, say the researchers, represents a step toward a future of higher performance memory devices.
At the most fundamental level, digital data is stored as a basic unit of information known as a bit, which is often represented as either a "one" or a "zero." Thus, the pursuit of better data storage comes down to finding more efficient ways to store and read these ones and zeros.
While flash memory has become extremely popular, researchers have been searching for alternatives that could further improve speed and simplify fabrication. One such candidate is nonvolatile resistive random-access memory (RRAM), which, instead of storing charge in transistors like flash memory does, uses materials that can switch between states of high and low resistance to represent ones and zeros.
"However," says Chun-Chieh Chang, professor at National Taiwan Normal University and one of the authors of a paper on the study, "the electrical measurements needed to check the resistance and read zeros and ones from RRAM can limit the overall speed. Recently, to overcome this issue, RRAMs have been combined with LEDs to develop something called light-emitting memories. In this case, the data can also be read by checking if the LED is on or off. This additional optical reading also opens new routes for carrying large amounts of information."
However, previous versions of such light-emitting memories required the integration of two separate devices with differing materials, complicating fabrication. To overcome this, the researchers turned to perovskite, a type of material with a crystalline structure through which ions can migrate to give it unique physical, optical, and even electrical properties. By controlling the ion migration, perovskite researchers have been constructing new materials with unique properties.