Carbon nanotubes: From disordered ensembles to van der Waals crystals

Carbon nanotubes (CNTs) have ignited worldwide excitement for their extraordinary electrical and mechanical properties. Yet, despite decades of effort, realizing the “dream material” for carbon-based electronics—a wafer-scale, perfectly aligned, single-chirality, densely packed array of semiconducting CNTs—has remained elusive. Here, we provide a perspective on the recent breakthroughs that are bringing this vision closer to reality. We highlight advances in both chemical vapor deposition (CVD) and post-growth assembly, culminating in the emergence of van der Waals (vdW) crystals of single-chirality CNTs self-assembled on atomically flat hexagonal boron nitride (hBN) surfaces. We discuss the fundamental mechanisms, device implications, and rich opportunities for interdisciplinary exploration in quantum physics, materials science, and electronics.

Carbon nanotubes (CNTs) are one-dimensional tubular structures that can be thought of as rolled-up graphene sheets. Since their serendipitous discovery in the early 1990s, CNTs have fascinated researchers across physics, chemistry, and engineering, holding the promise of a new technological revolution in nanoelectronics. Their unique one-dimensional nature gives rise to remarkable properties: ballistic transport, high current densities, and tunable electronic bands. These features make CNTs not only fascinating for fundamental study but also highly promising for next-generation electronics and optoelectronics. Each individual CNT can carry an electric current of approximately 10 μA, and given their extremely small diameter (about 1 nm), this translates to an astonishing current-carrying capacity per unit area. However, practical devices often require a much higher total current than a single nanotube can provide. As a result, recent research has increasingly focused on devices incorporating CNT films or CNT arrays within the channel to achieve greater overall current flow.

The last decade has seen remarkable milestones in the development and application of CNT-based electronics. In 2013, researchers achieved a groundbreaking feat by constructing the first simple computer with logic circuits entirely built from CNT thin-film transistors.1 Although this prototype operated with a basic architecture and at relatively slow speeds—far from the sophistication and performance of commercial silicon chips—it nonetheless marked a pivotal moment, demonstrating that carbon-based electronic systems could be realized in practice. In 2019, scientists developed a more complex CNT-based processor capable of running a 16-bit system, demonstrating substantial progress toward commercial chip manufacturing.2 By 2020, researchers successfully fabricated wafer-scale CNT transistors using commercial equipment originally designed for silicon semiconductor processing. This breakthrough confirmed the compatibility of carbon-based chip manufacturing with existing silicon-based production lines, significantly advancing the practical application of carbon-based chips.3 This breakthrough not only demonstrated the feasibility of integrating CNT-based device fabrication into the existing silicon-based semiconductor industry but also greatly advanced the prospects for the practical deployment of carbon-based chips in mainstream electronics.