Effect of the wire width on 1D magneto excitons in GaAs-AlGaAs quantum-well wires

Abstract

GaAs-Al x Ga 1− xAs quantum well wires (QWW) with lateral extensions between 100 and 60 nm have been realized by holographic lithography and reactive ion etching. In photoluminescence excitation and reflection spectroscopy two heavy hole (hh) type of excitations, hh 11 and hh 12, were observed, which result from one-dimensional (1D) subband states. The energy separation between these transitions was dependent on the wire-width. The 1D excitonic character of the transitions was in particular reflected in the magnetic field dispersion. From the diamagnetic shifts we determined exciton binding energies finding an enhancement of the ground-state hh-excitonic interaction in the QWWs, e.g., in 70 nm wide wires of about 15% compared to the original 2D system.