Abstract
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.