Mindinfrared unipolar photoluminescence in InAs/GaAs self-assembled quantum dots

We have investigated the midinfrared unipolar photoluminescence in InAs/GaA s self-assembled quantum dots. Resonant emissions between confined levels a re clearly observed at low temperature at around 10 mu m wavelength. The un ipolar emissions are polarized either in the layer plane or along the z gro wth axis of the quantum dots. The emissions are associated with hole transi tions that involve the ground and the excited hole states. The quenching du e to Pauli blocking of the unipolar emission lines involving the hole groun d state is observed when this state is completely filled. An intradot nonra diative lifetime tau approximate to 25 ps is deduced for the different leve ls from the midinfrared emitted power. [S0163-1829(99)14947-6].