Scientists have developed innovative supramolecular memristor nano-RRAM, demonstrating fast resistive switching and non-volatile storage capabilities. This breakthrough paves the way for advanced data storage technology and marks an important step in meeting the needs of the era of big data and artificial intelligence.
In the era of big data and advanced artificial intelligence, traditional data storage methods have become insufficient. To meet the demand for high-capacity and energy-efficient storage solutions, it is critical to develop next-generation technologies.
Among them, resistive random access memory (RRAM) relies on changing resistance levels to store data. A recent study published in the journal Angewandte Chemie details the work of a team of researchers who have pioneered a method to create supramolecular memristors, one of the key components in building nanoscale random-access memories.
A memristor (short for memory-resistor) changes resistance in response to an applied voltage. However, building memristors at the molecular scale is a huge challenge. While resistive switching can be achieved through redox reactions, and the charged state of the molecule is easily stabilized by counterions in solution, this stabilization is difficult to achieve in the solid-state junctions required for memristors.
Now, a research team led by Yuan Li at Tsinghua University in Beijing, China, has chosen a supramolecular approach. It is based on a bistable catenan, meaning it is stable in both its oxidized and reduced states and can exist in a positively, negatively or uncharged state. Catenanes are systems of two macromolecular rings that interlock like two links in a chain, but without chemical bonds.
To build the memristor, the team deposited catenanes onto gold electrodes coated with sulfur-containing compounds, binding them together through electrostatic interactions. On top of this, they placed a second electrode made of a gallium-indium alloy coated with gallium oxide. Catane forms a self-assembled monolayer of flat molecules between two electrodes. This combination, named AuTS-S-(CH2)3-SO3-Na+//[2]catenane//Ga2O3/EGaIn, forms a memristor.
As required by RRAM. These new supramolecular memristors can switch between a high-resistance state (off) and a low-resistance state (on) in response to an applied voltage. These molecular resistive switches achieve at least 1,000 erase-read (on)-write-read (off) cycles. The switching time between on and off is significantly less than one millisecond, which is comparable to commercial inorganic memristors.
Molecular switches "remember" their set state - on or off - within minutes. This makes them a very promising starting point for efficient molecular memristors with non-volatile storage capabilities. Furthermore, they also function as diodes or rectifiers, which makes them interesting components for the development of molecular nanomemristors.