Nonequilibrium radiation of long-wavelength InAs/GaSb superlattice photodiodes

The emission behavior of binary-binary type-II InAs/GaSb 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 gamma(ind n)=1x10(exp 24) cm6 s(exp -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 1x10(exp 16) cm-3. Furthermore, an analytic expression of the quantum efficiency for the radiation upon forward-bias conditions is given.