Low-temperature synthesis of ZnSe nanowires and nanosaws by catalystassisted molecular-beam epitaxy

Single-crystal ZnSe nanowires are grown on a prepatterned gold catalyst by molecular-beam epitaxy. Optimum selectivity and maximum nanowire densities are obtained for growth temperatures in the range 400-450 °C, but gold-assisted growth is demonstrated for temperatures as low as 300 °C. This suggests a diffusion process on/through the catalyst particle in the solid state, in contrast to the commonly assumed liquid phase growth models. Straight wires, as thin as 10 nm, nucleate together with thicker and saw-like structures. A gold particle is always found at the tip in both cases.