Background limited long wavelength infrared type-II InAs/GaSb superlattice photodiodes operating at 110 K

The utilization of the $P+-π-M-N+$ photodiode architecture in conjunction with a thick active region can significantly improve long wavelength infrared type-II InAs/GaSb superlattice photodiodes. By studying the effect of the depletion region placement on the quantum efficiency in a thick structure, we achieved a topside illuminated quantum efficiency of 50% for an $N$-on-$P$ diode at $8.0μm$ at 77 K. Both the double heterostructure design and the application of polyimide passivation greatly reduce the surface leakage, giving an $R0A$ of $416Ωcm2$ for a 1% cutoff wavelength of $10.52μm$⁠, a Shot–Johnson detectivity of $8.1×1011cmHz/W$ at 77 K, and a background limited operating temperature of 110 K with 300 K background.