ENHANCED EXCITON-PHONON SCATTERING IN INXGA1-XAS GAAS QUANTUM WIRES/

We have investigated the dephasing of excitons due to scattering by ac oustic phonons in quantum wires by means of temperature-dependent time -integrated four-wave mixing. Free-standing In0.35Ga0.865As/GaAs quant um wires with lateral sizes between 29 and 85 nm have been studied. By measuring the phase relaxation time of the excitonic resonance at low carrier densities, we have determined the homogeneous linewidth. From the temperature dependence of the homogeneous linewidth at temperatur es between 5 and 30 K, we have evaluated the temperature coefficient g amma(ac), which is a measure for the exciton-acoustic phonon scatterin g strength. gamma(ac) is found to increase with decreasing wire width. It is shown that this dependence on the wire width is consistent with a microscopic theory of exciton-acoustic phonon coupling.