Structural characterization and low temperature growth of ferromagnetic Bi–Cu codoped ZnO bicrystal nanowires

Abstract

Ferromagnetic Bi–Cu codoped ZnO nanowires were fabricated at temperatures as low as $300°\mathrm{C}$ via a vapor phase transport using the mixture of Zn, $\mathrm{Bi}{\mathrm{I}}_3$ and CuI powders. They are grown as a bicrystal, along the $\left[01\overline{1}2\right]$ direction, have a width of $40–150\mathrm{nm}$ , and a length of a few microns. The investigation of the growth mechanism proposes that the synergy of BiCu and iodine/iodide induces the formation of bicrystallinity. The photoluminescence measurement shows the cooperative effect of Bi and Cu ions. The ferromagnetism observed in this study is the result of the combined effect of structural defects, the substitution of Cu into Zn site along the $c$ axis, and codoping of Bi.