The structure and multifunctional behaviors of Mn-ZnO/Mn-ZnS nanocomposites

Mn-ZnO/Mn-ZnS nanocomposites have been synthesized by using Mn-ZnO nanorods as templates through a simple sulfidation reaction. The incorporated Mn dopants are in 2+ valence state and substitute for Zn²⁺ ions in both ZnO and ZnS host lattice. The Mn-ZnO nanorods display robust ferromagnetism as well as weak ultraviolet and visible emissions at room temperature. The coating of Mn-ZnS layer results in the decrease of ferromagnetism and the significant enhancement of visible emission in orange region. Meanwhile, the band gap of the nanocomposites increases as the sulfidation time prolongs. By studying the variation of ferromagnetism with the sulfidation time, it is concluded that the observed strong ferromagnetism in Mn-ZnO nanorods mainly originates from the surface region where the ferromagnetism is much stronger relative to the core area of the nanorods.