Barrier composition dependence of the internal electric field in ZnO/Zn1-xMgxO quantum wells

Time-integrated photoluminescence experiments are used to study the excitonic optical recombinations in wurtzite ZnO/Zn1-xMgxO single quantum wells of varying widths and magnesium compositions. By comparing experimental results with a variational calculation of excitonic energies, the authors determine the magnitude of the built-in electric field that is induced by both spontaneous and piezoelectric polarizations. It is found that the electric field varies linearly with magnesium composition. By taking into consideration the well-known distribution of electric field among the barrier and the well layers in multiquantum wells, the authors show that their results are fully consistent with previously reported data. (C) 2007 American Institute of Physics.