Minority carrier diffusion length and lifetime for electrons in a type-II InAs∕GaSb superlattice photodiode

We use the electron-beam-induced current (EBIC) technique to investigate carrier transport characteristics in a type-II InAs∕GaSb superlattice photodiode with cutoff wavelength at 7.7μm. We use a theoretical model that includes an extended generation source and depletion region to simulate the EBIC current on both sides of the p–n junction. The electron minority diffusion length in the p-superlattice, Le, is extracted from the simulation, from which the electron lifetime τe is obtained. Le increases from 0.275μm at 5.3Kto0.355μm at 100K. τe drops from 1.5ns at 5.3Kto0.13ns at 100K.