Excitonic and free carrier recombination in InxGa1-xAs/GaAs V-shaped quantum wire for different in content

We have investigated the optical properties of InxGa1-xAs/GaAs V-shaped qua ntum wires (0.1 < x < 0.2) by time integrated and magneto-photoluminescence experiments as a function of excitation power density and applied magnetic field at different temperatures. Tne experimental results indicate the dif ferent nature of the radiative recombination processes depending on the In concentration: in the deep quantum wires (x greater than or equal to 0.15) the recombination is excitonic, whereas free carriers seem to dominate in t he shallow wires (x = 0.10). We demonstrate that the actual recombination m echanism is primarily effected by the competition between confinement and b uilt-in piezoelectric field which governs the exciton binding energy. Speci fic theoretical models have been developed to interpret the experimental da ta.