Carrier quantum confinement in self-ordered ${\mathrm{Al}}_x{\mathrm{Ga}}_{1-x}\mathrm{As}$ V-groove quantum wells

Observation of quantum confined states and optical anisotropy of the interband absorption in self-ordered ${\mathrm{Al}}_x{\mathrm{Ga}}_{1-x}\mathrm{As}$ vertical quantum wells (VQW’s) grown on V-grooved substrates is reported. The variation in Al composition across the VQW’s was determined by parallel electron energy-loss spectroscopy. It was then employed to calculate the eigenstates of the confined carriers in these structures, with valence-band mixing included using a $4\times 4$ $\mathbf{k}\cdot \mathbf{p}$ Luttinger model. Polarized photoluminescence excitation spectra of the structure show features attributed to transitions between electron and heavy-hole or light-hole confined eigenstates, with measured energies in good agreement with the calculated ones. Polarization anisotropy associated with confined electrons and holes is evidenced by the measured spectra and explained by valence-band mixing in the (011) self-ordered quantum well.