Effect of catalyst particle interspacing on the growth of millimeter-scale carbon nanotube arrays by catalytic chemical vapor deposition

Vertically aligned millimeter-scale carbon nanotube (CNT) arrays have been successfully deposited on both Fe(3 nm)/Al2O3 and Fe(1 nm)/Al2O3 catalyst films under different optimum pretreatment conditions by catalytic chemical vapor deposition. By investigating the catalyst particles before CNT array growth, it has been found that inter-particle spacing plays a significant role in influencing CNT array height, CNT diameter and wall number in the present study. The growth kinetics of CNT arrays grown from the two catalyst films with different pretreatment conditions demonstrates a competitive lengthening-thickening process. Based on the kinetics studies, it has been proved that inter-particle spacing affects the CNT array height by affecting their lengthening time, and accordingly affects the diameter and wall number of CNTs because of the concurrent change in the thickening time.