Enhanced Binding Energy of One-Dimensional Excitons in Quantum Wires

Photoluminescence spectra are systematically studied on a series of 5 nm scale, T-shaped, GaAs quantum wires (QWRs). Potential profiles and quantized energies of QWRs are precisely determined as a function of structure parameters. By comparing the experimental quantized energy with the calculation without the Coulomb interaction, the binding energy $E_b$ of one-dimensional (1D) excitons is quantitatively evaluated. Upon increasing the 1D confinement, $E_b$ in QWRs is found to be enhanced to $27\pm 3\mathrm{meV}$, which is 6–7 times larger than the bulk value.