Anomalously large blueshift of donor-acceptor pair transition peak in GaAs/AlGaAs coupled quantum wells with low residual impurity densities

摘要

Summary form only given. We report our results on direct observation of an anomalously large blueshift as large as 12 meV in GaAs-AlGaAs QWs with low residual (undoped) impurity densities. Each photoluminescence (PL) spectrum consists of only the donor-acceptor pair (DAP) transition peak within the entire range of pump intensities. The sample was grown by molecular-beam epitaxy on a [100] semi-insulating n-type GaAs substrate.