Recent progress in W-structured type-II superlattice photodiodes

Recently we have achieved significant improvements in the performance of LWIR type-II superlattice photodiodes, with discrete devices beginning to demonstrate dynamic impedance-area product (R0A) levels approaching the MCT trend line and quantum efficiency exceeding 30% in devices without anti-reflection coatings. We discuss the key innovations that have led to these improvements, including modified W-structures, band-gap grading, and hybrid superlattices.