Effects of quantum mechanical coupling on the optical properties of vertically stacked V-groove quantum wires

The effects of the quantum mechanical coupling on the optical properties of vertically stacked InGaAs/GaAs V-shaped quantum wires have been studied by means of photoluminescence and photoluminescence-excitation spectroscopy. The experimental results have been analyzed by a simple theoretical model based on an analytical procedure. We found that by decreasing the barrier thickness (L-b) between the wires, the vertical coupling induces a splitting of the single wire levels into symmetric and antisymmetric states characterized by a polarization anisotropy. Furthermore, a clear shift of the coupled levels and a narrowing of the spectral linewidth are observed with a decrease in L-b. These findings are consistent with the theoretical predictions.