Single-molecule diode created

Australian and Spanish researchers have made a significant breakthrough in the quest to create smaller everyday electronic devices.

As explained by lead author Dr Nadim Darwish, from Curtin University, the physical limit of current computing power has been reached because today’s conventional technology is limited to allowing only the printing of millions of diodes on silicon chips, rather than thousands of billions.

“If we want to continue to offer smaller and more powerful everyday electronic devices like mobiles phones and laptops, then we have to use single molecules as the basic components of the electronic circuits in those devices,” Dr Darwish said.

This is exactly what Dr Darwish and his team set out to achieve, successfully creating a diode out of a tiny single molecule. Collaborating with researchers from the University of Barcelona and UNSW, their work has been published in the journal Nature Communications.

“Our method utilises a small organic molecule connected with a gold and a silicon electrode in a tiny circuit, measuring only 1 nanometre long — or about 100,000 times smaller than the width of a human hair,” said Dr Darwish.

“While we are not the first to have created single-molecule diodes, this diode is much smaller and more efficient than any previously reported. Using this technology, we can fit more than ten thousand billion diodes onto a 1 cm² area of a silicon chip, which will help make it easier to develop even smaller everyday electronic devices in the future.”

Co-author Dr Simone Ciampi, also from Curtin University, said the researchers are now focused on increasing the mechanical stability of the diodes. If they can do that, they could open up a range of exciting technological possibilities for modern electronic devices.

“We have demonstrated that this molecular-scale diode can allow currents to pass in one direction 4000 times more efficiently than in the opposite direction, which is a leap towards creating single-molecule diodes of comparable efficiency to conventional diodes while also scaling down the size significantly,” Dr Ciampi said.