Synthesis of highly dense and vertically aligned array of SWCNTs using a catalyst barrier layer: High performance field emitters for devices

Highlights: • Role of double catalysts Aluminium/Iron (Al/Fe) has been studied. • Al as buffer layer reduces the diffusion of Fe catalyst in Si substrate & provides more sites for the nucleation of SWCNTs. • Strong adhesion of Fe nanoparticles with Al provides the good alignment of SWCNTs. • Field emission parameters are enhanced due to high density, vertical aligned nature and uniformity of SWCNTs. - Abstract: The authors in this research investigated the role of double catalyst layer Fe/Al in the growth of SWCNTs to obtain high current density, low turn on field and high field enhancement factor to act as efficient field emitters. We synthesise SWCNTs by PECVD technique using Fe/Al as a dual catalyst layer on Si substrate. It is seen that during the growth of SWCNTs, Al act as a barrier layer which reduces the diffusion of Fe catalyst in Si substrate resulting in high density vertically aligned growth of SWCNTs. Field emission measurements show high current density 30.5 mA/cm² at very low turn-on field 1.2 Vμm⁻¹ with a high field enhancement factor of 1.6 × 10⁴. Stability and repeatability parameters of as-grown highly vertically aligned SWCNTs are also studied as a function of current density. Stability results show fairly stable field emitters for 7 h with good repeatability.