A new shortwave-midwave-longwave infrared photodetector that has the ability to realize a three-color has just been developed by Northwestern University's Manijeh Razeghi and her team. With the new design, the devices can detect different infrared wavebands by simply varying the applied bias voltage. This could open up a range of potential applications, including infrared color televisions and three-color infrared imaging.
Razeghi, who is an electrical engineering and computer engineering professor invented and investigated a new for three-color photodiodes without using additional terminal contacts with the help of her team of researchers. The resulting photodetector is based on indium-arsenide/gallium-antimonide/aluminum-antimonide type-II superlattices.
As the applied bias voltage varies, the photodetector sequentially exhibits the behavior of three different colors, corresponding to the bandgap of three absorbers, and achieves well-defined cut-off wavelengths and high-quantum efficiency in each channel.
This new research 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 infrared photodetector and two-color, shortwave-midwave infrared photodetector based on type-II superlattices.