Crossover from Excitons to an Electron-Hole Plasma in a High-Quality Single T-Shaped Quantum Wire.

We studied evolution of photoluminescence (PL) spectral with increasing excitation powers in an unprecedentedly high-quality quantum wire. The PL spectra obtained suggest that the transition from excitons to a dense electron-hole (e-h) plasma in the wire is a gradual crossover via bi-excitons. We also found that the continuum band edge of excitons shows no energy shift with increasing e-h densities and never crosses to the low-energy edge of the plasma PL at higher e-h densities, which is in contrast to a prevailing picture of the exciton Mott transition. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]