Excitonic states of weakly confining quantum wires

We consider theoretically the excitonic levels of weakly one-dimensional quantum wires in the regime where the center of mass of the exciton is confined by the wire potentials for the electron and hole. A general frame based on the effective-mass approximation is presented and the case of harmonic profiles for the electron and hole confining potentials is considered in detail. The breaking of translation symmetry by the wire potentials introduces a series of transitions between the 1S and 2S excitons of the underlying isolated well, which lead to an intrinsic high-energy tail for the wire absorption. We evaluate also the exciton scattering by longitudinal acoustical phonons and by alloy disorder in Ga1-xInxAs-based systems. (C) 1998 American Institute of Physics. [S0021-8979(98)01414-5].