Carrier-carrier interaction and fast intersubband scattering in wide GaAs quantum wells

Wide quantum wells, where the energy spacing between the first two energy levels is lower than the energy of the polar optical phonon, could represent the ideal condition to obtain a population inversion and the production of infrared lasers. On the other hand in these quantum wells the efficiency of carrier-carrier scattering is increasing with the width of the well and can produce a relatively quick relaxation of carriers in the first subband. In this work we present a detailed and systematic joint theoretical and experimental investigation considering different well width and carrier density and we conclude that in most cases the carrier-carrier scattering is sufficiently strong to forbid a significant population inversion.