Optical investigation of quantum-well fluctuations in In0.53Ga0.47As/InP superlattices

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Abstract
Photoluminescence spectra of In0.53Ga0.47As/InP multiple quantum wells with well widths of 70–160 Å and barrier widths of 20–400 Å exhibit narrow doublet lines or more complex line structure. Such spectra are studied as a function of temperature, excitation level, and wavelength, and by photoluminescence excitation spectroscopy. It is shown that all lines are due to intrinsic excitons and that the multiplicity of the spectra arises from fluctuations in the quantum wells along the growth direction, which we identify with compositional changes of the InGaAs. The multiline spectra offer a convenient way to study interwell electron‐hole transfer, and this process is shown to be efficient in the present crystals up to barrier widths of at least 200 Å.