Density dependence of radiative and nonradiative recombination rates in a gated GaAs/Ga1-xAlxAs modulation-doped quantum well

The recombination time of photoexcited carriers is measured by picosecond luminescence experiments in a GaAs/Ga1-xAlxAs modulation-doped quantum well at low temperature. The electron density is varied in the 0-3×1011 cm-2 range by the use of a Schottky gate. These results, combined with a measurement of the variation of the photoluminescence efficiency, evidence a decrease of the radiative rate and an increase of the nonradiative rate with increasing electron density. © 1989 The American Physical Society.