Near-room temperature MWIR HgCdTe photodiodes limited by vacancies and dislocations related to Shockley–Read–Hall centres

Trap assisted tunnelling via traps located at dislocation cores as well as mercury vacancies are considered as the mechanisms of enhanced thermal generation of charge carriers in reverse-biased MWIR HgCdTe photodiodes operating with Peltier cooling. Field-induced reduction of trap activation energies increases thermal generation and creates conditions for large tunnelling currents. The model for LWIR devices published previously in Ref. [20], also explain experimental current–voltage characteristics of the MWIR photodiodes assuming great misfit dislocation density at graded gap interfaces between absorber and contact regions.

► I–V characteristics of uncooled photodetectors are investigated.
► Trap assisted tunnelling is considered as the mechanisms enhanced thermal generation.
► Traps are located at dislocation cores and mercury vacancies.
► Misfit dislocations are occurred at graded gap interfaces of HgCdTe heterostructures.