LAUSR

Abstract Site selective growth of vertically aligned carbon nanotubes (VACNTs), using floating catalyst based chemical vapor deposition (FC-CVD), can be achieved by proper use of carbon nanotube growth inhibitors. Here, we present a detailed study on the inhibition properties of Au and Pt thin films in ferrocene catalyzed FC-CVD. Elemental composition and chemical state analysis, at different depths of the growth substrates, were performed using X-ray photoelectron spectroscopy. Propensity of Fe to diffuse into the growth substrate was stronger in the case of Pt coated SiO 2 as compared to Au coated or pristine SiO 2 substrates. Increase in catalyst concentration or decrease in film thickness resulted in a loss of inhibition action of Au, whereas inhibition action of Pt was unaffected. Diffusion of C, Si, Cr and O in Au were different from that in Pt. Our data provides new insights into growth inhibition processes and explains some of the contradictions in previously published reports. The inhibitor based FC-CVD technique was used to make flexible VACNT/polymer circuits, suitable for bio-electronic applications. Electrical sheet resistance, electrochemical double layer capacitance, and charge storage capacity of the VACNT/polymer films, were found to be approximately 135 Ω/□, 1 mF/cm 2 and 19 mC/cm 2 , respectively.