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

A three-color, shortwave-midwave-longwave IR photodetectorcould 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 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.