Single Molecule Diode Paves Way for Microscopic Electronics

Researchers at Columbia and Berkeley have successfully created an effective single molecule diode, a development that could lead to the creation of nano-scale electronic devices. The concept of a single molecule diode was first proposed in 1974 By Mark Ratner and Arieh Aviram, and has until now been a tantalizingly unachievable goal in nanotechnology. Now that a one-molecule diode has been developed, the world may be closer to seeing an entire electronic device contained in one molecule.


A diode basically acts as a gate for the flow of electricity. It only allows electricity to travel through it in one direction. Diodes are a crucial part of the circuits that power the electronic devices we use every day, including the microchips that make computers work. The single molecule diode is exciting because it will allow for a new phase in the miniaturization of electronics.


Although single molecule diodes have been created in the past, this new molecule outperforms previous attempts by far. The older single molecule diodes were simply molecules designed to have an asymmetrical structure. While the asymmetrical structure did give these molecules some of the properties of diodes, it was not enough to achieve completely unidirectional travel of current.

The new single molecule diode is more than 50 times more effective than its predecessors at making electricity flow only in one direction. It also conducts much more power: 0.1 microamps. The new diode achieves these remarkable results through simple means. Instead of focusing on making the molecule itself asymmetrical, the researchers introduced asymmetry into its environment. Since this single molecule diode is so easily constructed, it will be relatively simple to incorporate into current nano-scale devices.


Diodes are not the only electronic components that might be made out of a single molecule. Since Aviram and Ratner’s 1974 paper, scientists have been experimenting with turning molecules into electrical switches, transistors, and more. The hope is that eventually entire circuits will be built out of single-molecule components. The team of researchers that created the new diode will now focus on trying to understand more clearly the mechanics behind why their new device works.