One-Step Solvent-Free Synthesis and Characterization of Zn1[minus]xMnxSe[commat]C Nanorods and Nanowires

The carbon-encapsulated, Mn-doped ZnSe (Zn1 xMnxSe@C) nanowires, nanorods, and nanoparticles are synthesized by the solvent-free, one-step RAPET (reactions under autogenic pressure at elevated temperature) approach. The aspect ratio of the nanowires/nanorods is altered according to the Mn/Zn atomic ratio, with the maximum being observed for Mn/Zn1⁄4 1:20. A 10–20 nm amorphous carbon shell is evidenced from electron microscopy analysis. The replacement of Zn by Mn in the Zn1 xMnxSe lattice is confirmed by the hyperfine splitting values in the electron paramagnetic resonance (EPR) experiments. Raman experiments reveal that the Zn1 xMnxSe core is highly crystalline, while the shell consists of disordered graphitic carbon. Variable-temperature cathodoluminescence measurements are performed for all samples and show distinct ZnSe near-band-edge and Mn-related emissions. An intense and broad Mn-related emission at the largest Mn alloy composition of 19.9% is further consistent with an efficient incorporation of Mn within the host ZnSe lattice. The formation of the core/shell nanowires and nanorods in the absence of any template or structure-directing agent is controlled kinetically by the Zn1 xMnxSe nucleus formation and subsequent carbon encapsulation. Mn replaces Zn mainly in the (111) plane and catalyzes the nanowire growth in the [111] direction.