New transitions in the photoluminescence of GaAs quantum wells

When GaAs quantum wells are optically excited with intensities ≳10 kW/cm2 new peaks appear in the photoluminescence spectrum at low temperatures. The excitation spectra are used to demonstrate that the new peaks correspond to the recombination of electrons in excited well states, n≳1, with holes in n = 1 states. These parity-forbidden transitions, Δn odd, derive their strength from three body interactions that occur at high excitation levels.