Joint Centers of Excellence Program

Molecular Memory Devices Based on Charge Transfer Complexes (Domain 2, Project 3)

For more than three decades now computer hardware has evolved in a top-down manner by a hammer and chisel approach (from minimum feature sizes of micrometer to 10 nm on a chip nowadays) according to Moore’s Law—that is, the number of transistors that can be placed on a chip, with a halving in cost, has increased exponentially, doubling approximately every two years. The top-down approach for miniaturization of circuit elements is now reaching its end and a revolutionary approach needs to be exploited in order to address the challenge brought about by the “end of the roadmap.” It is anticipated that the future of nanoscale devices (below 100 nm) could well lie in the development of molecule-based electronics. The utilization of molecules as functional elements in molecular electronic devices (MEDs) is becoming increasingly attractive research area on account of the fact that the further size reduction of the circuit elements is turning out to be challenging with the conventional circuit elements. Miniaturization of electronic components will contribute to the development of more powerful supercomputers, as well as smart nanocomputers. Towards this end, we have explored molecular switches, namely, bistable mechanically interlocked molecules (MIMs), as active elements in molecular switch tunnel junctions (MSTJs) for molecular memory applications. Most remarkably, these bistable molecular switches have been incorporated successfully into 160 Kbit memory devices, demonstrating the promise that MIMs hold in MEDs. Despite the significant progress, there are still challenges that need to be addressed in these devices regarding their reproducibility and robustness as a result of the disorder and lack of robustness associated with self-assembled monolayers and polymer coating.