Minority electron unipolar photodetectors based on type II InAs/GaSb/AlSb superlattices for very long wavelength infrared detection

The bandstructure tunability of Type II antimonide-based superlattices has been significantly enhanced since the introduction of the M-structure superlattice, resulting in significant improvements of Type II superlattice infrared detectors. By using M-structure, we developed the pMp design, a novel infrared photodetector architecture that inherits the advantages of traditional photoconductive and photovoltaic devices. This minority electron unipolar device consists of an M-structure barrier layer blocking the transport of majority holes in a p-type semiconductor, resulting in an electrical transport due to minority carriers with low current density. Applied for the very long wavelength detection, at 77K, a 14μm cutoff detector exhibits a dark current 3.3 mA/cm², a photoresponsivity of 1.4 A/W at 50mV bias and the associated shot-noise detectivity of 4x10¹⁰ Jones.