Electronically Configurable Molecular-Based Logic Gates

TLDR

Resonant tunneling through molecular electronic states dominates current flow in the closed state of the device. Logic gates were built from arrays of redox‑active rotaxane switches sandwiched between metal electrodes, whose state was read by monitoring current at reducing voltages and irreversibly switched by oxidizing voltages, enabling the assembly of AND and OR gates. The resulting AND and OR gates exhibited high‑to‑low current ratios of 15 and 30, markedly exceeding typical wired‑logic performance.

Abstract

Logic gates were fabricated from an array of configurable switches, each consisting of a monolayer of redox-active rotaxanes sandwiched between metal electrodes. The switches were read by monitoring current flow at reducing voltages. In the "closed" state, current flow was dominated by resonant tunneling through the electronic states of the molecules. The switches were irreversibly opened by applying an oxidizing voltage across the device. Several devices were configured together to produce AND and OR logic gates. The high and low current levels of those gates were separated by factors of 15 and 30, respectively, which is a significant enhancement over that expected for wired-logic gates.