Evidence for barrier-to-well injection of carriers in high quality ZnO/Zn0.9Mg0.1O multiple quantum wells grown on (111) Si

► High quality ZnO/Zn0.9Mg0.1O multiple quantum wells were grown on (111) Si. ► The FWHM and τeff of emission from ZnO wells are 17 meV and 183 ps, respectively. ► Temperature-dependent PL is investigated to reveal the behavior of the carriers. ► Evidence for the barrier-to-well injection of carriers is indicated.