Dual-band pBp detectors based on InAs/GaSb strained layer superlattices

We report on fabrication of 320 × 256 dual-band (mid-/long-wave infrared) type-II InAs/GaSb strained layer superlattice (T2LS) focal plane array (FPA) with pBp architecture. The simplified fabrication procedure has been utilized to reveal the fundamental electro-optical performance of both absorbers in pBp dual-band detector structure. Dark current density of 2.7 × 10−6 A/cm2 (VBias = −0.1 V) and 1.1 × 10−6 A/cm2 (VBias = +0.1 V) was measured for LWIR and MWIR absorbers, respectively (85 μm × 85 μm device). The peak responsivities measured at 77 K were 1.6 A/W (at λ = 5 μm and Vb = +0.4 V) and 1.8 A/W (at λ = 9 μm and Vb = −0.7 V) for MWIR and LWIR absorbers with corresponding values of specific detectivity 5 × 1011 Jones and 2.6 × 1010 Jones, respectively (410 μm × 410 μm device).

► Fabrication of 320 x 256 dual-band (MW/LWIR) InAs/GaSb T2SL FPA with pBp architecture is reported
► Fundamental electro-optical performance of both absorbers in pBp MW/LWIR detector is discussed
► Details of GaSb substrate removal procedure for 320x256 MW/LWIR T2SL FPA are outlined