Low Dark Current, Extended Wavelength SWIR Sensors Using Hydrogenated nBn InGaAs

Improved performance SWIR sensors with extended wavelength response to 2.5 microns will be developed using two disruptive technologies with which Amethyst has demonstrated success: nBn detector structures and defect passivation via hydrogenation. Similar to conventional extended wavelength photodiodes, the improved sensors will based on mismatched InGaAs grown on graded buffer layers on InP substrates. Conventional photodiodes in mismatched InGaAs suffer performance degradation that is related to excess dark current related to defect processes. These photodiode structures will be replaced with nBn detector structures, which have been demonstrated to be very effective in suppression of defect processes in materials closely related to mismatched InGaAs. Additional suppression of defect-related dark current will be accomplished via defect-passivation of the mismatched InGaAs nBn materials. This work will build on recent studies by Amethyst, demonstrating hydrogenation-produced dark current suppression in mismatched InAs nBn devices. This recent success with hydrogenated mismatched nBn"s in InAs is directly relevant to the extended wavelength mismatched InGaAs nBn materials, which are 80% InAs. Order of magnitude dark current reduction is anticipated in extended wavelength sensors with high quantum efficiency operating between T=200K and room temperature.