Spatially Confined CVD Growth of High-Density Semiconducting Single-Walled Carbon Nanotube Horizontal Arrays

High-density horizontally aligned single-walled carbon nanotube (SWNT) arrays with high-purity semiconducting tubes are promising materials for energy-efficient electronics. However, realizing high density and high semiconducting purity through the direct-growth method is still a challenge. Here the problem is overcome through a spatially confined approach based on a floating solid catalyst chemical vapor deposition (FSCCVD) system. A confined space is designed to change the fluid dynamics in a chemical vapor deposition reactor, offering a trapping effect for both catalyst nanoparticles and carbon fragments. Therefore, densely and uniformly distributed catalyst nanoparticles are continuously deposited on substrates, greatly increasing the growth probability and efficiency of SWNTs. Besides, the solid catalyst TiC and the oxygen-vacancy-enriched catalyst TiO both facilitate the growth of semiconducting tubes. As a result, SWNT horizontal arrays with a high density of 65 tubes mu m(-1) and a semiconducting purity of >95% are realized, which hold the potential for future application in carbon nanotube electronics.