Excitons and biexcitons in semiconductor quantum wires

The exciton and biexciton ground-state binding energies are calculated for semiconductor quantum wires of radius R smaller than the bulk exciton radius a₀ assuming an infinite confining potential. Both the excitonic and biexcitonic (molecular) binding energies are enhanced by a factor greater than 5 for GaAs/Ga_1-x{Al}ₓ$As quantum wires of radius approximately ${a}₀$/2. The simultaneous shrinking of the exciton size with the wire radius is shown to reduce the contribution (when compared with the quasi-two-dimensional case) of dielectric polarization effects which arise when the wire is embedded in a cladding with a lower dielectric constant.