Radiation Hardened Interceptor LWIR Type-II Superlattice-based Seeker Sensors

The aim is to demonstrate that Type-II InAs/GaSb superlattices (T2SLs) will exhibit significantly improved radiation hardness in comparison to the existing state-of-the-art HgCdTe-based sensors. T2SL-based sensors consist of III-V compound semiconductors which have much stronger bonding than II-VI-based sensors, and should be less susceptible to ionizing and nuclear particle radiation. This will we experimentally verified during this project and new techniques for radiation hardening of T2SL-based sensors will be developed. New insight will be gained by putting forward density distribution models and then comparing the predicted output with all experimental data for close verification. Having identified the source of the problems and in order to improve current hardness performance, the superlattice and device design will be optimized. In detail, this means paying special attention to achieve best passivation under radiation conditions, and the possibility of chemically modifying current polymers materials for optimized radiation blockage. Dark current and mechanisms such as defect assisted tunneling are other parameters which need special attention and optimization. This will be done by developing thin film radiation filters grown on top of the photodetectors and then quantitatively demonstrating the radiation hardness of T2SL-based sensors and their viability under long-term exposure to space radiation. Approved for Public Release | 16-MDA-8917 (15 November 16)