The dark current of a type-II InAs/GaSb strained layer superlattice photodiode with an n-i-p structure is reduced by using an active gate bias technique. To make the gate structure on the mesa sidewall of the photodiode, we used Si3N4 and Ti/Au as a dielectric film and a gate metal, respectively. At 77 K, the dark current density of the photodiode with a gate bias (VG = −30 V) applied on the mesa side wall is reduced by more than one order of magnitude compared to the dark current density at zero gate bias. At 77 K, the product of the dynamic differential resistance and the area at a gate bias of −30 V shows a 12 times improvement compared to the same measurement at zero gate bias.
Infrared Photodetector Superlattice InAs GaSb Passivation Dark current