Measurement of interface recombination velocity in (Pb,Sn)Te/PbTe double-heterostructure laser diodes

The effective minority-carrier lifetime in the active region of Pb0.86Sn0.14Te/PbTe double-heterostructure (DH) laser diodes has been experimentally determined for a series of diodes with active-region widths ranging from 0.7 to 3.9 μm using a measurement technique which involves observing the dependence of the threshold current density on the duration of a current pulse input. From the data, it is inferred that the interface recombination velocity at the heterojunctions is as high as 1×105 cm/sec at 5 °K, while the bulk minority-carrier lifetime is 4.3 nsec. For a typical double-heterostructure laser with a 2-μm active-region width, this implies a reduction in the internal quantum efficiency due to interface recombination of as much as 80%.