Graphene Light Detector Spans IR Spectrum

A new light detector is the first to sense the full IR spectrum, carrying potential advancements in heat-vision technology.

The room-temperature, graphene-based detector, developed by a team at the University of Michigan, can be made thin enough to be stacked on a contact lens or integrated with a cellphone.

“If we integrate it with a contact lens or other wearable electronics, it expands your vision,” said researcher Zhaohui Zhong, an assistant professor at the university. “It provides you another way of interacting with your environment.”

The detector features a new way of generating an electrical signal. Until now, graphene could not capture enough light to create such a signal. “The challenge for the current generation of graphene-based detectors is that their sensitivity is typically very poor,” Zhong said. “It’s a hundred to a thousand times lower than what a commercial device would require.”

In developing the device, the researchers looked at how light-induced electrical charges in the graphene affected a nearby current. They placed an insulating barrier layer between two graphene sheets, with current running through the bottom layer. Light hitting the top layer freed electrons and created holes with positive charge. The electrons used quantum mechanics to pass through the barrier and into the bottom layer of graphene.

The technique makes a room-temperature graphene device more sensitive and more efficient than existing mid-infrared detectors, which require cumbersome cooling equipment to operate. The new detector is quite small and can easily be scaled down, according to the researchers.

The work is published in Nature Nanotechnology.

For more information, visit: www.umich.edu.