Optical studies of modulation-doped V-groove quantum wires: Fermi-edge singularity

We report on an experimental study of the optical properties of modulation- doped V-groove semiconductor quantum wires. The Fermi-edge singularity is o bserved in emission and only weakly in absorption spectra. The conditions n ecessary for its observation are assessed by varying the electron density a nd providing the occupation of one, two or three one-dimensional (1D) subba nds. We show that the existence of a strong optical singularity is related to both the effect of the hole localization and that of an enhancement indu ced by Coulomb correlations with a resonance associated with a partially em pty 1D subband. (C) 2001 Elsevier Science B.V. All rights reserved.