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Gradient stainless steel buffer layer to support aluminium nitride diffusion barrier for carbon nanotubes growth

Abstract:

We propose a new effective method to keep the catalyst nanoparticles on the surface of bulk stainless steel 304 (SS304) to grow carbon nanotubes (CNTs). This method consists on the creation of a buffer layer of nitrided stainless steel and a top barrier layer of aluminium nitride (AlN). For that, we have followed two steps. A first step consists on a DC-pulsed reactive sputtering process from SS304 target and a second step of reactive sputtering from aluminium target. Stainless steel nitrided layer (G-SS304) was produced by increasing the nitrogen concentration in the Ar atmosphere in order to obtain a gradient buffer layer on SS304. On the other hand, the AlN layer was produced by a fixed nitrogen concentration in the argon atmosphere. The catalyst nanoparticles were performed on top of the multilayer system after the deposition of an ultrathin Fe layer, which transforms in a monolayer of isolated Fe nanoparticles acting as catalyst during CNTs growth. The aim of this study is to present an alternative methodology for producing CNTs grown on stainless steel. We used different temperatures to obtain CNTs: 680, 700, 715 and 730°C. Scanning electron microscope (SEM) images showed the influence of temperature over the performance of this new configuration. Raman characterization provided structural information about the CNTs. One of the applications of this method is the production of high specific surface electrodes based on stainless steel for electrochemical devices.