Nonequilibrium radiation of long-wavelength InAsGaSb superlattice photodiodes

The emission behavior of binary-binary type-II InAsGaSb superlattice photodiodes has been studied in the spectral range between 8 and 13 μm. With a radiometric calibration of the experimental setup the internal and external quantum efficiencies have been determined in the temperature range between 80 and 300 K for both the negative and positive luminescences. The negative luminescence efficiency approaches values as high as 35% without antireflection coating. An analytic description of the temperature dependence of the internal quantum efficiency around a zero-bias voltage allows for the determination of the coefficient for electron-hole-electron Auger recombination Γ_n =1× 10²⁴ cm⁶ s^-1. For an n -type material, the minority-carrier lifetime is provided as a function of band gap and temperature, explaining the strong decrease of the minority-carrier lifetime in the case of an n -type residual background exceeding 1× 1016 cm-3. Furthermore, an analytic expression of the quantum efficiency for the radiation upon forward-bias conditions is given.