Carrier relaxation in intermixed GaAs/AlxGa1−xAs quantum wires

Time-resolved investigations on the photoluminescence of GaAs/${\mathrm{Al}}_{\mathit{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As quantum wires as a function of the wire width and the potential well depth indicate a reduction of the energy relaxation in quasi-one-dimensional (1D) systems. The systematic change of the wire width and potential well depth of the quantum wires with mask widths down to 40 nm were realized by ion-implantation-induced intermixing of quantum wells. Lifetime measurements on the high-energy side of the quantum wire emission yield increased decay times for the smallest wires. This is consistent with our observation of increased carrier temperatures and slowed cooling in the quantum wires with increasing carrier confinement. We explain the reduction of the relaxation with the decreased possibility for the scattering particles to fulfill both energy and momentum relaxation in wires with gradually increasing 1D behavior.