Femtosecond laser modification of an array of vertically aligned carbon nanotubes intercalated with Fe phase nanoparticles

Abstract

Femtosecond lasers (FSL) are playing an increasingly important role in materials research, characterization, and modification. Due to an extremely short pulse width, interactions of FSL irradiation with solid surfaces attract special interest, and a number of unusual phenomena resulted in the formation of new materials are expected. Here, we report on a new nanostructure observed after the interaction of FSL irradiation with arrays of vertically aligned carbon nanotubes (CNTs) intercalated with iron phase catalyst nanoparticles. It was revealed that the FSL laser ablation transforms the topmost layer of CNT array into iron phase nanospheres (40 to 680 nm in diameter) located at the tip of the CNT bundles of conical shape. Besides, the smaller nanospheres (10 to 30 nm in diameter) are found to be beaded at the sides of these bundles. Some of the larger nanospheres are encapsulated into carbon shells, which sometime are found to contain CNTs. The mechanism of creation of such nanostructures is proposed.

Vertically Aligned Carbon Nanotube Membranes: Water Purification and Beyond

“…This distinctive process can be used to synthesize VACNTs in bulk quantities. Labunov et al demonstrated the possibility of generating a VACNT bundle with a small diameter (10–30 nm) via the femtosecond laser irradiation of metal (Fe)-phase catalyst containing graphite [ 34 ]. Although the laser ablation process rapidly produces high-quality CNTs, its high energy consumption, limited scale-up potential, and lower grade of CNT purity limit its use in practical applications.…”

Изменение Химического Состояния И Концентрации Железа В Углеродных Нанотрубках, Полученных Методом CVD И Подвергнутых Импульсному Ионному Облучению

“…2, c и d). Формирование графитовой оболочки, возможно, связано с частичной абляцией слоев нанотрубок и диф-фузией углерода через поверхность частиц железа [26]. Исследование методом РФЭС показало снижение доли окисленного железа при облучении импульсным ионным пучком с плотностью энергии 0.5 J/cm 2 (рис.…”

Laser Patterning of Aligned Carbon Nanotubes Arrays: Morphology, Surface Structure, and Interaction with Terahertz Radiation

“…Another technique is the post-growth treatment based on the ablation of an array by a focused laser beam. Applications of femtosecond [17][18][19][20][21] and nanosecond [17,[22][23][24][25][26][27] pulsed and continuous [17,[28][29][30][31] lasers were considered. Due to the high longitudinal thermal conductivity of nanotubes and significantly suppressed radial heat transfer [32,33], the patterning of arrays with shortpulse lasers does not provide a decisive benefit in the quality of cut edges [17] as it is used for the ablation of dense targets [34].…”