Optical investigation of quantum well fluctuations in In sub (0.53) Ga sub (0.47) As/InP superlattices grown by chemical beam epitaxy.

Photoluminescence spectra of In sub (0.53) Ga sub (0.47) As/InP multiple quantum wells grown by chemical beam epitaxy with well widths of 70 - 160angstroms and barrier widths of 20 - 400angstroms 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 multi-line spectra offer a convenient way to study interwell exciton transfer, and this process is shown to be efficient in the present crystals up to barrier widths of at least 200angstroms.