Temperature dependence of Auger recombination in a multilayer narrow-band-gap superlattice

Temperature and density-dependent Auger recombination rates are determined for a four-layer broken-gap superlattice designed for suppression of both Auger recombination and intersubband absorption. The structure is intended as the active region of both optically pumped and diode lasers operating in the midwave infrared. Auger recombination and intersubband absorption are thought to be among the primary factors contributing to high-threshold current densities in such devices. Ultrafast time-resolved photoluminescence upconversion was used to measure the Auger rates at lattice temperatures ranging from 50 to 300 K. Results are compared to calculated rates using the temperature-dependent, nonparabolic K⋅p band structure and momentum-dependent matrix elements. The calculations, which include umklapp processes in the superlattice growth direction, are in excellent agreement with the experimental results. Comparison of these results with those obtained in other mid-IR semiconductor structures verifies Auger suppression. The measured temperature-dependent Auger recombination rates, together with calculations of the gain, provide an upper bound for the characteristic temperature, $T_0=81\mathrm{}\mathrm{K},$ for lasers utilizing this superlattice as an active region.