High-Detectivity VLWIR Type-II Superlattice Infrared Photo Detectors

Current technology for detecting long wavelength and very long wavelength infrared light, such as mercury cadmium telluride-based sensors, suffers from deleterious characteristics such as high noise and high cost. Creating detectors that operate in this wavelength range that reduce noise and cost will foster further implementation into remote sensing systems. SVT Associates proposes an innovative photodiode design based on strain-compensated type-II superlattice structure to improve very-long-wavelength infrared (VLWIR) detection. The end result of the combined Phase I Phase II effort will be a new generation of robust photodiodes and focal plane arrays capable of infrared detection beyond wavelengths of 30 microns. Commercial Applications and Other Benefits: Photo detector arrays using this material are of great interest to the DOE for various applications including, in particular, imaging and remote sensing. These VLWIR photo detectors can also find application to infrared-based chemical identification systems and terrestrial mapping. Applying the detection improvement in VLWIR region, dark current suppression and impurity reduction process to the superlattice should result in higher optical absorption, higher operating temperature, higher material purity, and very low dislocation density, all important factors that should significantly enhance device operation in 300-1000 cm-1 region.