Controlling The Carrier Lifetime Of Nearly Threading-Dislocation-Free Zno Homoepitaxial Films By 3d Transition-Metal Doping

Carrier lifetime in nearly threading-dislocation-free ZnO homoepitaxial films was controlled by doping 3d transition-metals (TMs), Ni and Mn. The photoluminescence lifetime of the near-bandedge emission (tau(PL)) was decreased linearly by increasing TM concentration, indicating that such TMs are predominant nonradiative recombination centers (NRCs). From this relationship, exciton capture-cross-section (sigma(ex)) of 2.4 x 10(-1)5 cm(2) is obtained. Because rex of native-NRCs (Zn-vacancy complexes) is likely larger than this value, the linear dependence of the internal quantum efficiency on tau(PL) observed in our TM-doped ZnO and unintentionally doped ZnO in literatures indicates that the concentrations of native-NRCs in the latter are "lower than" 10(16)-10(17) cm(-3). (C) 2016 AIP Publishing LLC.