Most photodetectors offered by VIGO are made of mercury-cadmium telluride compound (MCT) by Metalorganic Chemical Vapour Deposition (MOCVD) technology. Despite many advantages of MCT compound, including lattice parameter being almost independent on composition, nowadays in some applications, detectors containing mercury, cadmium and lead are successively removed from the consumer market through norms and directives (e.g. RoHS) due to their toxicity. The abovementioned limitations connected to MCT encouraged the company to find alternative material system and technology as a replacement. Inspired by literature, VIGO decided to develop Ga-free InAs/InAsSb superlattices which are a great candidate, operating in a similar wavelength regime from MWIR to VLWIR. We continue our idea of backside-illuminated devices using substrate material (GaAs) as an immersion lens. We still take advantage of detector material lattice-matched to the buffer layer, replacing CdTe and HgCdTe by GaSb and InAs/InAsSb SL, respectively. The architecture of SLs-based heterostructures originates from MCT photovoltaic devices and utilizes wide bandgap depletion layers for dark current reduction. The detectivity of SL devices is similar to MCT (Fig. 1). Currently, VIGO efforts are focused on the development of HOT LWIR photodiodes including thin absorber devices.
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