Graphite coating heralds microelectromechanical relays for harsh environments

While solid-state transistors have long been the workhorse of electronics, there is a limit to their energy efficiency as they tend to leak current, particularly at higher temperatures.

Microelectromechanical and nanoelectromechanical relays have zero current leakage, and consume very little power. They can also operate at much higher temperatures and levels of radiation than transistors.

The devices could be used to create extremely energy efficient electronic components with integrated sensing, processing and actuation, capable of operating in very harsh environments.

However, making the devices reliable has so far proven a challenge, according to Dr Dinesh Pamunuwa, who leads Bristol University’s Microelectronics research group.

“They are essentially nano-switches, with two electrodes that come into physical contact and break contact millions of times,” he said.  “That causes the contact to degrade, so after a certain amount of cycling the relays stop working.”

Now he and colleagues at the Universities of Bristol and Southampton, working with California-based Microsemi, have demonstrated that the relays can be made to operate reliably by coating them with nanocrystalline layers of graphite.