Horizontally aligned carbon nanotube scaffolds for freestanding structures with enhanced conductivity

Abstract

An unprecedented enhancement in electrical conductivity of horizontally aligned carbon nanotube (HA-CNT) structures using a 10 nm conformal coating of alumina (Al₂O₃) or amorphous silicon carbide (a-SiC) is presented. By combining the capability to grow long vertically aligned CNTs (VA-CNTs) with a liquid-assisted flattening technique, dense arrays of HA-CNTs exhibiting a high degree of alignment are realized and integrated at wafer-scale. Suspended structures, ranging from large area membranes to narrow beams, can be fabricated. The impressive enhancement in electrical conductivity, approximately 209% for the Al₂O₃ coated HA-CNTs (Al₂O₃/HA-CNTs) and 2276% for the a-SiC ones (a-SiC/HA-CNTs), demonstrates the potential of CNT-based scaffolds as scalable and functional building blocks for suspended interconnects, heat spreaders and novel chemical and optical sensors.