Controlling the carrier lifetime of nearly threading-dislocation-free ZnO homoepitaxial films by 3d transition-metal doping

• Published in: Applied physics letters Vol. 108; no. 2
• Main Authors: Chichibu, S F, Kojima, K, Yamazaki, Y, Furusawa, K, Uedono, A
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 11-01-2016
• Subjects: Absorption cross sections; Applied physics; Carrier lifetime; Dependence; Dislocations; Doping; Manganese; Nickel; Photoluminescence; Quantum efficiency; Transition metals; Zinc oxide
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4939838

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-band-edge emission (τPL) was decreased linearly by increasing TM concentration, indicating that such TMs are predominant nonradiative recombination centers (NRCs). From this relationship, exciton capture-cross-section (σex) of 2.4 × 10−15 cm2 is obtained. Because σex of native-NRCs (Zn-vacancy complexes) is likely larger than this value, the linear dependence of the internal quantum efficiency on τPL 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.