Photoluminescence of Cd1-xMnxS (x ≤ 0.3) nanowires

Cd1-xMnxS (x = 0.1 - 0.3) nanowires were synthesized by using the chemical vapor deposition method. They all consist of a single-crystalline wurtzite CAS structure with a [010] or [011] growth direction. The X-ray diffraction pattern reveals the contraction of the lattice constants due to the incorporation of Mn. The Mn2+ emission at similar to 2.15 eV, originating from the d-d (T-4(1) -> (6)A(1)) transition, appears below 50-80 K. Its decay time is in the range of 0.55-1 ms, showing a decrease with increasing Mn content. The Mn doping reduces significantly the decay time of band-edge emission from 590 ps to 20 - 30 ps. Upon applying magnetic field (up to 7 T), the Mn2+ emission is suppressed and donor-acceptor pair emission becomes dominant, suggesting the energy transfer from the band electrons to the Mn2+ ions.