An International Team of Researchers Work to Combine a Diode and Resistor Into a Single Device

June 08, 2020 by Luke James

A team of researchers with ties to the University of Central Florida (UCF) has created a new type of molecular circuit switch which could bring a new era of ultra-high-density computing.

Creating smaller and faster devices that do not compromise on performance and energy efficiency has been a goal of electronic and design engineers worldwide for several years now. 

However, the power that is required for today’s designs has a tendency to overheat, which can damage circuits that are generally built by connecting a diode switch in series with a memory element.

This is known as one-diode-one resistor, an approach that requires large voltage drops across the device, translating into higher power requirements. It also makes shrinking circuits and designing smaller designers more difficult by limiting it because two separate circuit elements are required. 

Today, many research teams are working on combining the diode and resistor into a single device thanks in part to the demand placed on them from electrical and design engineers who could take advantage of such a device to design the next generation of consumer electronics. 


One-on-One Molecular Switches

Although these one-on-one switches are viable options, they have been limited by only being able to carry out a single function and were often plagued with problems including unstable voltage variances and limited lifespans.

Now, an international team headed by Christian Nijhuis from the National University of Singapore, alongside co-authors Damien Thompson at the University of Limerick and Enrique del Barco the University of Central Florida, has created a new type of molecular switch that works as both a diode and a memory element.

The one-on-one switch, which is only 2 nanometers thick, only requires a low drive voltage of under 1 Volt. "The community is quickly advancing in identifying novel electronic device applications at the molecular scale," says Del Barco, a professor who specializes in quantum physics. "This work may help speed-up the development of new technologies involving artificial synapses and neural networks."


Enrique del Barco from the University of Central Florida.

The international team, which includes UCF physics professor Enrique del Barco (pictured), has created a new type of molecular switch that works as both a diode and memory element. Image credited to University of Central Florida

How the Switch Works

The switch works following a two-step mechanism where the injected electrical charge is stabilized by the migration of charged ions between the molecules and the device surface, something made possible by bonding the molecules in pairs. 

According to the team’s paper, by using a combination of electrical measurements and atomic-scale measurements, the research team discovered a spot between stability and switchability, that resulted in dual diode and memory resistive RAM memory at a microscopic scale. 

The research team is calling their discovery a “significant breakthrough” but admits more work is needed in the area before real-world applications and experiments can be considered.