[20p-S222-1~17] 21.1 Joint Session K

[20p-S222-10] Controlling the carrier lifetime of nearly threading-dislocation-free ZnO homoepitaxial films by 3d transition-metal doping

〇Shigefusa Chichibu¹, Kazunobu Kojima¹, Yoshiki Yamazaki¹, Kentaro Furusawa¹, Akira Uedono² (1.IMRAM, Tohoku Univ., 2.Univ. of Tsukuba)

Keywords:Zinc Oxide,Time-resolved Photoluminescence,PL lifetime

Carrier lifetime in nearly threading-dislocation-free ZnO homoepitaxial films was controlled by doping 3d transition-metals (TMs) such as Ni and Mn. The photoluminescence lifetime of the near-band-edge emission was decreased linearly by increasing TM concentration, [TM], indicating that such TMs are predominant nonradiative recombination centers (NRCs). From this relationship, exciton capture-cross-section of 2.4x10^-15 cm² is obtained. Because exciton capture-cross-section of native-NRCs (Zn-vacancy complexes) is likely larger than this value, the linear dependence of the internal quantum efficiency on the PL lifetime 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" 10¹⁶-10¹⁷ cm^-3.