Sensitive Longwave Infrared Sensors Based on P-on-N Type-II Strained Layer Superlattices

We propose to develop high-sensitivity longwave (cutoff ~ 10-12 microns) infrared sensors for space situational awareness applications from Type-II InAs/GaSb strained layer superlattices (SLS). One novelty of our approach lies in using a P-on-N photodiode design (in contrast to the usual N-on-P) to leverage the excellent low-noise readout multiplexers available to drive P-on-N diode arrays. In Phase 1, we will develop material and passivation and measure their quality via test diode arrays that we will fabricate and test. Quality permitting, a companion 320x256 array will be hybridized to a readout, post-processed into a focal plane array (FPA), and tested for imaging performance. In Phase 2, we will further develop growth and processing with the aim of achieving FPAs with high quantum efficiency, low noise, and high pixel uniformity and operability. Several FPAs will be delivered.