Impact of quantum confinement and quantum confined Stark effect on biexciton binding energy in GaN/AlGaN quantum wells.

We report on time-resolved photoluminescence measurements carried out along the thickness gradient of two types of GaN/AlGaN quantum wells with low Al content in the barriers (5% and 9%, respectively). A reduction of the biexciton binding energy with increasing well thickness is observed, as a result of the reduced quantum confinement and the increasing impact of the quantum confined Stark effect. In the sample with 5% Al content in the barriers, for thicknesses of the well region larger than ∼9 monolayers, the biexciton binding energy is found to be smaller than that measured for bulk GaN. [ABSTRACT FROM AUTHOR]