We demonstrate very-long-wavelength infrared type II InAsGaSb superlattice photodiodes with a cutoff wavelength (λc,50%) of 17 μm. We observed a zero-bias, peak Johnson noise-limited detectivity of 7.63× 109 cm Hz12 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 (R0 A) measurements indicated that silicon dioxide passivation increased surface resistivity by nearly a factor of 5, over unpassivated photodiodes, and increased overall R0 A uniformity. The bulk R0 A at 77 K was found to be 0.08 Ω cm2, with RA increasing more than twofold at 25 mV reverse bias.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)