Electric field induced decrease of photoluminescence lifetime in GaAs quantum wells

Time-resolved photoluminescence measurements of excitons in GaAs-Ga _1-xAl_xAs quantum wells subject to an electric field perpendicular to the well plane have been made. With increasing field, both integrated luminescence (as previously reported) and luminescence lifetime decrease. Thus the electric field increases the exciton nonradiative decay rate. Estimates of several possible mechanisms suggest that Fowler-Nordheim tunneling is responsible for the quenching. With increasing pump laser intensities, larger electric fields are required to quench the lifetime because of exciton screening of the field.