Subband structure of GaAs coupled quantum wires on V-grooved substrate

The subbands structure of crescent shaped GaAs coupled quantum wires is clearly observed by photoluminescence excitation (PLE) measurements. In the PLE spectra of single quantum wires (wire thickness=4.5 nm), sharp exciton peaks of the first two heavy hole-like transitions are observed with large energy difference of 47 meV. However, two adjacent peaks with small energy splitting of 24 meV are observed in the coupled quantum wires (wire thickness=5 nm, barrier thickness=3 nm). From the measurements of the barrier thickness dependence, these peaks agree well with the symmetric and antisymmetric states of the coupled quantum wires calculated by the finite element method