The first room-temperature light detector that can sense the full infrared spectrum has the potential to put heat vision technology into a contact lens.
Unlike comparable mid- and far-infrared detectors currently on the market, the detector developed by University of Michigan engineering researchers doesn’t need bulky cooling equipment to work.
“We can make the entire design super-thin,” said Zhaohui Zhong, assistant professor of electrical engineering and computer science. “It can be stacked on a contact lens or integrated with a cell phone.”
To make the device, they put an insulating barrier layer between two graphene sheets. The bottom layer had a current running through it. When light hit the top layer, it freed electrons, creating positively charged holes. Then, the electrons used a quantum mechanical trick to slip through the barrier and into the bottom layer of graphene.
The positively charged holes, left behind in the top layer, produced an electric field that affected the flow of electricity through the bottom layer. By measuring the change in current, the team could deduce the brightness of the light hitting the graphene.
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