MBE growth and characterization of type-II InAs/GaSb superlattices LWIR materials and photodetectors with barrier structures

In the paper the whole heterojunction structure design process in LWIR type-II InAs/GaSb superlattices (T2SLs) detectors has been presented. The high quality T2SLs materials were grown and the high performance double heterojunction LWIR detectors have been fabricated. In the double heterojunction LWIR detectors a electrons barrier layer and a holes barrier layer were designed and introduced successively, based on the electrical properties measurement and compensation doping of the T2SLs intrinsic material. The processed double heterojunction structure photodiodes had a 100% cutoff wavelength of 12.5 μm at 80 K. The peak current responsivity was 2.5 A/W under zero applied bias, corresponding to a quantum efficiency of 30%. The R0A product at 80 K is 14.5 Ω cm2 which leads to the peak detectivity D∗ of 1.4 × 1011 cm Hz1/2/W for the detector.