Characteristics of exciton binding energy in a hybrid InGaN/MgZnO quantum well without internal field

Exciton binding energies in a hybrid InGaN/MgZnO quantum well (QW) structure without internal field have been calculated using numerical simulations based on the multiband effective-mass theory and characterized in comparison with those of the conventional InGaN/GaN QW structure with polarizations. Due to the depolarization effect, the hybrid QW has a large and nearly constant value of the optical momentum matrix element independent of the well width, in contrast to the conventional QW that its optical matrix element dwindles down to zero with increasing well width. As the well width increases, the exciton binding energies in the InGaN/MgZnO QW are always larger than those in the InGaN/GaN QW and their decaying rate is lower than that in the conventional QW. In addition, the exciton stability in the hybrid QW is higher than that in the conventional QW against growing sheet carrier density.