Black silicon maskless templates for carbon nanotube forests

We present here a proof of concept for a novel fabrication method of vertically aligned carbon nanotube forests, utilizing black silicon nanograss (a forest of silicon nanometer-sized spikes created with reactive ion etching) coated with titanium tungsten diffusion barrier as a template. The method allows maskless definition of carbon nanotube forests with control of their density, nanotube diameter and height. Four nanograss reactive ion etching recipes are investigated and their wafer-to-wafer repeatability, wafer uniformity, and density control is discussed. Evaluation of carbon nanotube forests grown on the nanograss substrates is presented with discussion of their morphology, diameter distribution, and catalyst thickness influence.

Vertically aligned carbon nanotube forest can be grown on black silicon nanograss coated with titanium tungsten. In optimal conditions, one nanotube is grown from one nanograss pillar. Thus, good control of the nanograss density and morphology provides a maskless method for definition of the CNT forest.Figure optionsDownload as PowerPoint slideHighlights
► We propose a novel method for patterning of catalytically grown carbon nanotube (CNT) forests.
► We experimentally evaluate application of silicon nanograss as the pattern platform for the CNTs.
► We show how to control nanograss morphology with a maskless reactive ion etching processing.
► We evaluate how the silicon nanograss properties translate to the properties of CNT the forest.