Fundamental limits of MWIR HgCdTe barrier detectors operating under non-equilibrium mode

• Theoretical investigation of MWIR HgCdTe barrier detectors was done.
• Different HgCdTe barrier detectors with n- and p-type absorber layer were discussed.
• Temperature-dependent electrical performances of HgCdTe barrier devices were analyzed.
• I–V plots of detectors with n-type absorber are dominated by diffusion currents.
• p-Type absorber provides lower dark currents at near-room temperatures.

The paper presents numerical considerations of temperature-dependent performance of different mid-wave infrared HgCdTe detectors (with p- and n-type active layer) for non-equilibrium operation. Current–voltage characteristics of double heterostructure PpN photodiode, pBppN barrier photodiode, nBnn and nBnnN barrier detectors are compared to find an optimal architecture for high-operating temperature conditions. Using our model, the calculated characteristics of the devices are fitted to the experimental results for HgCdTe photodiode grown on GaAs substrate by metal organic chemical vapour deposition.The performance of photodiodes with p-type absorber are limited by the generation current associated with the Shockley–Read–Hall process, while nBnn type devices (with the n-type absorber) indicate a diffusion limited dark currents associated with Auger processes. At high values of the reverse bias (over 1 V), the trap states located at dislocations lead to strong band-to-band and trap-assisted tunnelling due to high electric field within the depletion layer.