title: Role of sp-d exchange interactions in room-temperature photoluminescence and ferromagnetism of CuCo Co-doped ZnO nanorods.
abstract: CuCo co-doped ZnO nanorods have been synthesized via a soft chemistry route without using any surfactant, seed and catalyst. Structural analyses reveal that the samples of nominal compositions Cu0.01Co0.02Zn0.97O and Cu0.02Co0.01Zn0.97O have single hexagonal wurtzite structure without forming any extra secondary phase. Photoluminescence (PL) measurements show that the Cu co-doping in Co doped ZnO nanorods strongly influences the optical band structure and gives significant red shifts in the PL spectra. Furthermore, magnetic measurements of CuCo co-doped ZnO nanorods exhibit obvious room temperature ferromagnetism at low concentrations of Cu (< 1%) co-doping, while at higher concentrations of Cu co-doping, magnetization drops off sharply. An experimental relationship has been found to explain the redshift of E(g) edge in PL and the origin of observed ferromagnetism as function of Cu co-dopant concentration due to the spin exchange interactions between the sp band and localized spins of d electrons of dopants, which is useful for future semiconductor based spintronic devices.
authors.affiliation: Laboratory of Advanced Materials, Department of Material Science and Engineering, Tsinghua University, Beijing 100084, China.
authors.forename: Javed
authors.initials: J
authors.lastname: Iqbal
authors.forename: Baiqi
authors.initials: B
authors.lastname: Wang
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Liu
authors.forename: Huichao
authors.initials: H
authors.lastname: Zhu
authors.forename: Dapeng
authors.initials: D
authors.lastname: Yu
authors.forename: Ronghai
authors.initials: R
authors.lastname: Yu