Quantum-Dot Cellular Automata at a Molecular Scale

Quantum-dot cellular automata (QCA) is a scheme for molecular electronics in which information is transmitted and processed through electrostatic interactions between charges in an array of quantum dots. QCA wires, majority gates, clocked cell operation, and (recently) true power gain between QCA cells has been demonstrated in a metal-dot prototype system at cryogenic temperatures. Molecular QCA offers very high device densities, low power dissipation, and ways to directly integrate sensors with QCA logic and memory elements. A group of faculty at Notre Dame has been working to implement QCA at the size scale of molecules, where room-temperature operation is theoretically predicted. This paper reviews QCA theory and the experimental measurements in metal-dot QCA systems, and describes progress toward making QCA molecules and working out surface attachment chemistry compatible with QCA operation.