Photoluminescence of an InAlAs/InGaAs Quantum Well Structure Grown on a GaAs Substrate

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Abstract
An In0.53Ga0.47As/In0.52Al0.48As quantum well structure was grown on a GaAs substrate by molecular beam epitaxy. A linearly graded InGaAlAs layer grown at 380°C was used as a buffer layer. The photoluminescence of this structure was observed at 15 K. The InGaAs quantum well thicknesses ranged from 20 Å to 500 Å. Emission of each quantum well was clearly resolved. The luminescence linewidths were analyzed and compared to the results reported for the material system grown lattice-matched to InP. We deduced an enhancement of the alloy clustering and well thickness fluctuations which probably do not exceed 1 monolayer but which have a large lateral extension. These features are related to the lattice mismatch of the structure with the substrate.