Tunable built-in electric field and optical properties in wurtzite ZnO/MgZnO quantum wells

Based on the effective-mass approximation, the built-in electric field, exciton states and optical properties are investigated theoretically in the wurtzite (WZ) ZnO/MgZnO quantum wells (QWs). Numerical results show that the built-in electric field, exciton states and optical properties can be tuned effectively by the MgZnO barrier layer in the QWs. When the MgZnO barrier width is decreased, the built-in electric field Fw and the interband emission wavelength are decreased. However, the exciton binding energy and the electron-hole recombination rate increase with increasing the MgZnO barrier width. In particular, the electron-hole recombination rate approaches zero when the QWs structural parameters are large in the WZ ZnO/MgZnO QWs.