Improved performance III-V quantum well IR photodetectors: Review of current and potential focal plane technology

The maturation of the m-V materials technology has provided an opportunity for the development of a producible and affordable class of Infrared (IR) detector arrays. Designs based on the GaAs compounds permit the realization of multiple Quantum Well IR Photodetectors (QWIPs) which are useful for long wavelength focal plane arrays (8 - 10 mu m) with sizes demonstrated up to 640x480. Similar designs using InP based materials can cover an even broader IR spectral region with lattice matched structures. QWIP demonstrations have been made for midwave detectors (3 - 5 mu m) and very long wave detectors (up to 15 mu m) as well. New detector structures that improve optical performance and reduce bias current can lead to higher performance QWIPs which approach the performance of mercury cadmium telluride at moderate operating temperatures (similar to 80 K). These developments offer the possibility of practical, large, affordable IR focal plane arrays in the near future.