Design of an Auger-Suppressed Unipolar HgCdTe NBνN Photodetector

A unipolar mercury cadmium telluride (HgCdTe) NBνN infrared (IR) device architecture is analyzed by physics-based numerical device simulations. The device structure is predicted to suppress Shockley–Read–Hall (SRH) and Auger generation–recombination (G–R) processes, while also providing a simplified fabrication process by eliminating p-type doping requirements. The performance characteristics of mid- and long-wavelength infrared (MWIR: λc = 5 μm; LWIR: λc = 12 μm) NBνN devices are calculated and compared with those of nBn and double-layer planar heterostructure (DLPH) devices. Theoretical dark current density (Jdark) values of the MWIR and LWIR NBνN devices are lower by an order of magnitude or more for temperatures between 50 K and 225 K. Calculated peak detectivity (D*) values of 6.01 × 1014 cm Hz0.5/W to 2.36 × 1010 cm Hz0.5/W for temperatures from 95 K to 225 K, and 2.37 × 1014 cm Hz0.5/W to 2.27 × 1011 cm Hz0.5/W for temperatures from 50 K to 95 K are observed for MWIR and LWIR NBνN structures, respectively. A component of the NBνN structure, embodied in a unipolar MWIR nBn device, is also fabricated to experimentally demonstrate selective carrier extraction.