Mid-wavelength infrared planar junction photodetector based on InAs/GaSb Type-Ⅱ superlattices

• A planar junction MWIR photodetector based on InAs/GaSb T2SLs was fabricated using MBE growth and Zn thermal diffusion, achieving a 50% cut-off wavelength of 5.26 μm at 77 K. • The device exhibits a low dark current density of 8.67 × 10−5 A/cm2, a high quantum efficiency of 42.5%, and a peak detectivity of 3.90 × 1010 cm·Hz1/2/W at 77 K. • The effects of different Zn diffusion temperatures on dark current performance were systematically studied, optimizing the fabrication process. • A 640 × 512 focal plane array (FPA) was successfully fabricated, achieving a noise equivalent temperature difference (NETD) of 539 mK, demonstrating practical imaging capability.