MWIR barrier detectors versus HgCdTe photodiodes

• We theoretically simulated and compared Jdark and NEDT of HgCdTe photodiodes and nBn T2SLs detectors.
• Jdark of AIIIBV barrier detectors is higher than bulk HgCdTe photodiodes in MWIR range.
• To reach full potential of AIIIBV barrier detectors, short SRH carrier lifetime and passivation issues must be overcome.
• In case of HgCdTe nBn structure passivation process and contact layers processing should be improved.

New trends to reach high operating temperature (HOT) conditions to include AIIIBV bulk materials and type-II superlattices barrier structures have been observed. The barrier structures are designed to limit dark current associated with Shockley–Read–Hall (SRH) generation–recombination processes and to decrease influence of surface leakage current without impeding photocurrent. This idea is typically implemented in materials with poor SRH lifetimes, such as all AIIIBV compounds. Despite advantages of the AIIIBV barrier detectors over HgCdTe photodiodes to include reduced tunneling and surface leakage currents and suppressed Auger recombination, the performance of these detectors in comparison with HgCdTe photodiodes, has not been realized yet. It must be stressed that their dark current density is higher than that of bulk HgCdTe photodiodes, especially in mid-wave spectral range (MWIR). To explore full potential of barrier detectors, the technological restrictions such as short carrier lifetime and passivation issues must be overcome.