Electric field induced exciton binding in a GaAs/AlGaAs quantum well

Abstract

The effect of electric fields on exciton binding in a high quality, nominally undoped GaAs/AlGaAs single quantum well was investigated using low temperature photoluminescence and photoluminescence excitation spectroscopies. As electric fields, applied perpendicular to the well, swept electron/hole wavefunctions toward the two interfaces, exciton binding by impurity states was enhanced. The binding energy exhibited a minimum when wavefunctions were concentrated at the center of the well and a maximum when they were concentrated near the interfaces. The densities of binding sites had a maximum near the interfaces and a difference between the binding site densities at normal and inverted interfaces was observed.