High temperature laser assisted synthesis of boron nanorods, nanowires and bamboo‐like nanotubes.

A double-pulsed laser ablation (DPLA) method has been used to synthesize crystalline boron nanorods (BNRs), boron nanowires (BNWs), and bamboo-like boron nanotubes (BBNTs) from bulk boron (BKB). A q-switched Nd: YAG laser operating at the first and second harmonic wavelengths with 1064 and 532 nm is used to ablate a solid composite boron target doped with 1% Ni and 1% Co in a tube furnace in flowing argon gas. Boron nanostructures in the form of BNRs, BNWs, and BBNTs are condensed from the hot laser-induced plasma plume at furnace temperatures of 800, 900, and 1000 degrees C. The morphology and the chemical and optical nature of the nanostructures are identified from X-ray diffraction, electron microscopy, energy-dispersive X-ray spectroscopy, Raman, UV-vis, and photoluminescence (PL) spectroscopies. The results confirm the crystallinity and phase purity of the boron-nanomaterials and that they are preferentially grown in the c-axis direction of alpha-boron. The as-synthesized BNRs, BNWs, and BBNTs are observed to have lengths of 0.2-1.5 mu m and widths between 10 and 100 nm, and show respective PL resonance emission peaks at 330, 331, and 333 nm, and the electrical conductivities of 312, 313, and 324 S cm(-1) at room temperature which are higher than the electrical conductivity of BKB.