Dependence of excitonic energies on barrier thicknesses: A case of ZnO/Mg0.1Zn0.9O multi-quantum wells

Both theoretical calculation and room temperature photoluminescence (PL) measurements were employed to investigate the optical properties of ZnO/Mg0.9Zn0.1O multi-quantum wells (MQW). Firstly, we calculated the ground state energies of the excitons located in ZnO MQWs through a facile Kronig-Penney model. A clear increase of the excitonic energies was observed with narrowing the well layers or broadening the barrier regions due to the well-known quantum confinement effects (QCE). Besides, it was found that the dependence of exciton transition energies on barrier thickness could be fitted by a simple Arrhenius formula. Afterwards, a few PL measurements have been done over those MQWs, which exhibited a good agreement with theoretical analysis.