On the performance and surface passivation of type II InAs∕GaSb superlattice photodiodes for the very-long-wavelength infrared

We demonstrate very-long-wavelength infrared type II InAs∕GaSb superlattice photodiodes with a cutoff wavelength (λc,50%) of 17μm. We observed a zero-bias, peak Johnson noise-limited detectivity of 7.63×109cmHz1∕2∕W at 77 K with a 90%–10% cutoff width of 17 meV, and quantum efficiency of 30%. Variable area diode zero-bias resistance-area product (R0A) measurements indicated that silicon dioxide passivation increased surface resistivity by nearly a factor of 5, over unpassivated photodiodes, and increased overall R0A uniformity. The bulk R0A at 77 K was found to be 0.08Ωcm2, with RA increasing more than twofold at 25 mV reverse bias.