First observation of anomalously large blueshift of apparent donor-acceptor pair transition peak in compensation-doped quantum wells

Summary form only given.Previously, in undoped and doped bulk GaAs with donor and acceptor densities, the maximum amount of blueshift of the donor-acceptor pair (DAP) transition peak observed is only -3 meV. For the first time, to the best of our knowledge, we have observed anomalously large blueshift of the DAP transition peak (-11 meV) in compensation-doped asymmetric-coupled quantum wells (QWs). Our sample was grown by MBE on a semi-insulating GaAs substrate. The epitaxial layers consist of 20 periods, each of which is composed of two GaAs QWs, respectively, coupled by a Al/sub 0.53/Ga/sub 0.47/As barrier.