Synthesis of well-aligned boron nanowires and their structural stability under highpressure

Abstract

Owing to its unusual bonding and vast variety of unique crystal structures, boronis one of the most fascinating elements in the periodic table. Here we report thelarge-scale synthesis of well-ordered boron nanowires and their structural stabilityat high pressure. Boron nanowires with uniform diameter and length grownvertically on silicon substrates were synthesized by radio-frequency magnetronsputtering with a target of pure boron using argon as the sputtering atmospherewithout involvement of templates and catalysts. Detailed characterization byhigh-resolution transmission electron microscopy and electron diffraction indicatesthat the boron nanowires are amorphous. Structural stability of the boronnanowires at room temperature has been investigated by means of in situhigh-pressure energy-dispersive x-ray powder diffraction using synchrotronradiation in a diamond anvil cell. No crystallization was observed upto a pressure of 103.5 GPa, suggesting that the amorphous structure ofboron nanowires is stable under high pressure at ambient temperature.