Transition from excitonic to plasma emission from localized electron-hole pair states in GaAs-AlGaAs quantum wells



We present a theoretical analysis of the emission of localized excitons in GaAs-AlGaAs quantum wells, which shows a strong nonlinear behavior with increasing excitation. Considering the influence of dynamical screening both on the one-particle properties of carriers and on the whole spectrum of electron-hole pair states, we are able to explain the nonlinearity as a transition of the emission from excitonic to electron-hole pair states in the continuum (electron-hole plasma). Moreover, our theoretical approach based on the quasi-particle approximation for the carriers states and quantum kinetic effects in the screening describes the observed changes of the shift of the exciton energy from higher to lower energies at a temperature of T = 10 K (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)