Carrier lifetime studies in midwave infrared type-II InAs/GaSb strained layer superlattice

The authors report on an investigation of the dependence of the minority carrier lifetime in midwave infrared InAs/GaSb strained layer superlattices on a number of varied parameters: layer placement of two dopants (either Be or Te), and interface treatment between InAs and GaSb layers. In samples where the dopant and doping location was varied, it was found that the nonintentionally doped control sample exhibited the longest lifetimes (∼49 ns at 77 K under low injection), followed by the Be-doped and the Te-doped samples. Regardless of the type of doping, samples with dopants in only the InAs layer appeared to have longer lifetimes [low injection: 15 ns (Be), <3 ns (Te); high injection: 38 ns (Be), 16.2 ns (Te) at 77 K] compared to samples with dopants in the GaSb layer or all layers. However, because trap saturation behavior was observed in the transient photoluminescence (PL) decay, the intensity-dependent PL lifetime is a function of both the minority and majority carrier lifetimes, complicating the in...