High performance bias-selectable three-color Short-wave/Mid-wave/Long-wave Infrared Photodetectors based on Type-II InAs/GaSb/AlSb superlattices

TLDR

The authors propose a bias‑selectable three‑color infrared photodetector architecture based on InAs/GaSb/AlSb type‑II superlattices. They achieve channel‑specific turn‑on voltages by exploiting conduction‑band offsets and differential doping between two absorption layers. Optimizing these parameters yields experimentally demonstrated photodiodes that sequentially activate three distinct color bands with well‑defined cut‑offs, high quantum efficiency, and the flexibility to operate as single or dual‑band detectors at elevated temperatures, all without additional contacts.

Abstract

Abstract We propose a new approach in device architecture to realize bias-selectable three-color shortwave-midwave-longwave infrared photodetectors based on InAs/GaSb/AlSb type-II superlattices. The effect of conduction band off-set and different doping levels between two absorption layers are employed to control the turn-on voltage for individual channels. The optimization of these parameters leads to a successful separation of operation regimes; we demonstrate experimentally three-color photodiodes without using additional terminal contacts. As the applied bias voltage varies, the photodiodes exhibit sequentially the behavior of three different colors, corresponding to the bandgap of three absorbers. Well defined cut-offs and high quantum efficiency in each channel are achieved. Such all-in-one devices also provide the versatility of working as single or dual-band photodetectors at high operating temperature. With this design, by retaining the simplicity in device fabrication, this demonstration opens the prospect for three-color infrared imaging.