  We exploit the influence of the Coulomb interaction between electrons and
holes on the electron spin relaxation in a (110)-GaAs quantum well to unveil
excitonic signatures within the many particle electron-hole system. The
temperature dependent time- and polarization-resolved photoluminescence
measurements span five decades of carrier density, comprise the transition from
localized excitons over quasi free excitons to an electron-hole plasma, and
reveal strong excitonic signatures even at relatively high densities and
temperatures.
