3-Color Photodetector Explored for IR Color Television, Imaging Systems

A three-color, shortwave-midwave-longwave IR photodetector could be used to create IR color televisions and imaging systems.

"A device capable of detecting different IR wavebands is highly desirable in next-generation IR imaging systems," said professor Manijeh Razeghi of Northwestern University.

Razeghi and her team invented and investigated the design for three-color photodiodes without using additional terminal contacts. The resulting device is based on InAs/GaSb/AlSb type-II superlattices. As the applied bias voltage varied, the photodetector sequentially exhibited the behavior of three different colors, corresponding to the bandgap of three absorbers, and achieved well-defined cut-off wavelengths and high-quantum efficiency in each channel, the researchers said.

This research, published in Scientific Reports (doi: 10.1038/srep24144) builds on the Razeghi group's many years of work in Northwestern's Center for Quantum Devices, including the development of the first single-color, short-wavelength IR photodetector and two-color, shortwave-midwave IR photodetector based on type-II superlattices.