Dark current mechanisms investigation of surface passivation InAs/GaSb photodiodes at low temperatures

Abstract The dark current mechanisms were investigated at low temperatures (4–77 K). By optimizing the diodes fabrication processes and introducing SiO2 dielectric layer, the surface leakage was effectively suppressed even in smaller diameter (50 μm) with 607 Ω cm2 zero-bias resistance area product (R0A) at 77 K, which was 6 times higher than the R0A of unpassivated diode. In lower temperatures, the diffusion and generation–recombination (GR) current were not dominant contributing mechanisms to the total dark current. Qualitatively current density–voltage (J–V) modeling showed trap-assisted tunneling dominated behavior of dark current at temperatures lower than 50 K.