Resonance effects in Raman scattering from InAs/AlSb quantum wells

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Abstract
Resonant Raman scattering has been used to study GaSb‐capped AlSb/InAs/AlSb quantum wells, grown by molecular‐beam epitaxy with a shutter sequence intended to promote the formation of an InSb‐like InAs/AlSb heterointerface. For optical excitation in resonance with the E1 band gap of InAs, scattering by one‐longitudinal‐optical (LO) phonon and by two‐LO phonons from the quantum well layer is strongly enhanced. Excitation close to the E1/E1+Δ1 gap resonance of GaSb, in contrast, enhances the one‐LO scattering from the GaSb cap over that from the InAs quantum well. Thus resonance effects in LO phonon Raman scattering allow us to distinguish between scattering from these two materials despite the near‐coincidence of the corresponding LO phonon frequencies. Scattering by an InSb‐like mode is found to resonate at approximately the InAs E1/E1+Δ1 gap energy, supporting its assignment to an interface mode.