Radiative recombination mechanisms in staggered-alignment (GaAs)/(AlAs) heterostructures

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Abstract
This paper presents a detailed analysis of the radiative recombination mechanisms in staggered-alignment (GaAs)/(AlAs) heterostructures based on information obtained from optical measurements. The dominant momentum-mixing mechanisms are modeled as electron-phonon coupling and incoherent scattering by disorder at the interface, although a weak coherent-scattering term must be included to account for the strength of the zero-phonon line at long delays. The random-scattering mechanism leads to a distribution of decay rates, accounting for the nonexponential decay of the emission after pulsed excitation. As the excitation density or temperature is raised, more carriers are present in shallower or unbound states, resulting in emission at higher energies and faster decay rates. A comparison of the spectra and decay statistics among different samples reveals systematic trends in the electron-phonon and disorder scattering rates.