Advancements in small-pitch high-resolution DWB and HOT MWIR arrays at Leonardo UK

Leonardo UK (LEUK) has been manufacturing HgCdTe (MCT)-based infrared detectors using a unique Metal Organic Vapor-Phase Epitaxy (MOVPE) growth process for over 20 years. This growth technique enables the development of bandgap engineered MCT heterostructures, optimised for high performance in dual-waveband (DWB) and high operating temperature (HOT) MWIR applications.

LEUK has previously reported DWB MWIR/LWIR arrays (1280x1024/12μm) with near-BLIP performance and high operability in both wavebands. However, the need to incorporate two absorber regions in the structure meant that these arrays showed reduced quantum efficiency (QE) in both MWIR (~52%) and LWIR (~38%) compared to single-waveband devices. This paper reports LEUK’s latest developments in DWB arrays, targeting increased QE while maintaining EO performance through use of a purposefully designed MCT heterostructure. The latest DWB arrays (1280x1024/12μm), measured at 80K using f/2, have demonstrated an improved QE of 60% in both MWIR and LWIR wavebands. Median NETD has been measured to meet the Condor HD spec of 15 mK in MW and 30 mK in LW. These results show that band structure engineering continues to be an effective means of improving performance in both MWIR and LWIR.

In 2024 and 2025, LEUK reported HOT MWIR arrays (640x512/16μm) which incorporated a band engineered MCT heterostructure to achieve a near BLIP NETD of ~15 mK at 150 K. This paper aims to demonstrate the scalability of these band engineering principles by developing HOT MWIR arrays with larger format and smaller pitch than previously reported. The HOT MWIR array (1280x1024/12μm) reported here achieves close to BLIP performance at 140 K with a median NETD of 14.1 mK using f/2 at 50% well fill. Median NETD increases to only 28.9 mK at 170 K. These results demonstrate LEUK’s HOT technology can be scaled to larger formats and smaller pitches with minimal performance degradation.