Highly resilient field emission from aligned single-walled carbon nanotube arrays chemically attached to n-type silicon

Abstract

Single-walled carbon nanotubes (SWNTs) were chemically attached to an n-type silicon (100) substrate (n-Si) by exposing the surface to a nanotube-containing suspension for attachment times varying from 2 to 72 h. The SWNTs were imaged by atomic force microscopy (AFM) revealing a high density of vertically aligned SWNT bundles. Cyclic voltammetry experiments demonstrated that the n-type character of the substrate was maintained after the chemical attachment process. The SWNT/n-Si surfaces were found to field emit with a turn-on field ranging from 1.37–1.64 V µm⁻¹. From the Fowler–Nordheim (F–N) plots the field enhancement factor, β, was found to vary between ∼5000–7000 depending upon attachment time, which is consistent with changes in the sharpness of the SWNT tips as shown by AFM. The robustness of the field emitters was tested by maintaining a constant current and measuring the change in voltage required. The structures were found to have excellent stability over several days. The prospect for chemically attached SWNT arrays in field emission displays is discussed.