High Performance Planar Antimony-Based Superlattice Photodetectors Using Zinc Diffusion Grown by MBE

In this letter, we report a mid-wavelength infrared (MWIR) planar photodetector based on InAs/InAs_1−xSb_x type-II superlattices (T2SLs) that has a cut-off wavelength of 4.3 μm at 77 K. The superlattice for the device was grown by molecular beam epitaxy while the planar device structure was achieved by Zinc diffusion process in a metal–organic chemical vapor deposition reactor. At 77 K, the peak responsivity and the corresponding quantum efficiency had the value of 1.42 A/W and 48% respectively at 3.7 μm under −20 mV for the MWIR planar photodetector. At 77 K, the MWIR planar photodetector exhibits a dark current density of 2.0 × 10⁻⁵ A/cm² and the R₀A value of ~3.0 × 10² Ω∙cm² under −20 mV, which yielded a specific detectivity of 4.0 × 10¹¹ cm·Hz^1/2/W at 3.7 μm. At 150 K, the planar device showed a dark current density of 6.4 × 10⁻⁵ A/cm² and a quantum efficiency of 49% at ~3.7 μm under −20 mV, which yielded a specific detectivity of 2.0 × 10¹¹ cm·Hz^1/2/W.