Homochiral carbon nanotube van der Waals crystals.

For applications of single-walled carbon nanotubes (SWNTs) in integrated circuits, it is crucial to have high–tube density arrays of SWNTs that are well aligned and purely semiconducting. In this work, we report on the direct growth of close-packed SWNT arrays on hexagonal boron nitride (hBN) substrates, demonstrating high alignment and uniform chirality within each array. Molecular dynamics simulations suggest that a self-assembly growth mechanism resulted from the intertube van der Waals attraction and the ultralow sliding friction of SWNTs on the atomically flat hBN substrate. Field-effect transistors constructed from the grown SWNT array exhibit high performance at room temperature, with mobilities of up to 2000 square centimeters per volt per second, on/off ratios of ~107, and a maximum current density of ~6 milliamperes per micrometer. Editor's summary: Growing crystalline, two-dimensional arrays of single-walled carbon nanotubes on hexagonal boron nitride enables high-performance field-effect transistors. Zhang et al. have shown that van der Waals interactions between the nanotubes drive their alignment and create a uniform intertube spacing on the low-friction surface. Field-effect transistors showed high carrier mobilities up to 2000 square centimeters per volt per second and on/off ratios higher than 107. —Phil Szuromi [ABSTRACT FROM AUTHOR]