SIZE DEPENDENCE OF EXCITON-EXCITON SCATTERING IN SEMICONDUCTOR QUANTUM WIRES

The exciton dephasing kinetics due to exciton-exciton scattering is st udied in In0.135Ga0.865As/GaAs quantum wires both experimentally and t heoretically as a function of the wire width. By degenerate four-wave mixing studies, we observe a strong increase of the exciton-density-de pendent dephasing rate for decreasing wire widths between 85 nm and 29 nm. This surprising result is explained quantitatively within a multi subband model in terms of the increase of the exchange part of the exc iton-exciton interaction with increasing confinement. [S0163-1829(98)0 1419-2].