Rational Modification of a Metallic Substrate for CVD Growth of Carbon Nanotubes

Abstract

Growth of high quality, dense carbon nanotube (CNT) arrays via catalytic chemical vapor deposition (CCVD) has been largely limited to catalysts supported on amorphous alumina or silica. To overcome the challenge of conducting CNT growth from catalysts supported on conductive substrates, we explored a two-step surface modification that involves ion beam bombardment to create surface porosity and deposition of a thin AlxOy barrier layer to make the surface basic. To test the efficacy of our approach on a non-oxide support, we focus on modification of 316 stainless steel (SS), a well-known inactive substrate for CNT growth. Our study reveals that ion beam bombardment of SS has the ability to reduce film thickness of the AlxOy barrier layer required to grow CNTs from Fe catalysts to 5 nm, which is within the threshold for the substrate to remain conductive. Additionally, catalysts supported on ion beam-damaged SS with the same AlxOy thickness show improved particle formation, catalyst stability, and CNT growth efficiency, as well as producing CNTs with higher quality and density. Under optimal reaction conditions, this modification approach can lead to CNT growth on other nontraditional substrates and potentially benefit applications that require CNTs be grown on a conductive substrate.

A review of thermal interface material fabrication method toward enhancing heat dissipation

“…Several substrates are damaged when exposed to high temperatures and are limited to various applications. Although CNTs firmly attach to the substrate and display good surface contact, the applied operating temperature is unsuitable, particularly for the conductive substrate in device fabrication 80 . In certain cases, CNTs grow on the substrate and form carbon nanostructure (CNS, mixture of CNTs and carbon nanofiber), thus reflecting the total thermal conductivity in TIMs 70 .…”

“…Although CNTs firmly attach to the substrate and display good surface contact, the applied operating temperature is unsuitable, particularly for the conductive substrate in device fabrication. 80 In certain cases, CNTs grow on the substrate and form carbon nanostructure (CNS, mixture of CNTs and carbon nanofiber), thus reflecting the total thermal conductivity in TIMs. 70 In addition, the as-produced CNS that contained metal catalysts and unwanted impurities will have inconsistent thermal reading and effects the quality of the CNTs.…”

Hot-filament CVD Growth of Vertically-aligned Carbon Nanotubes on Support Materials for Field Electron Emitters

“…Carbon nanotubes have potential applications, including interconnects for supercapacitors, fuel cells, electron emitting devices [1][2][3][4][5]. For these applications, a direct assembly of the vertically-aligned carbon nanotubes (VACNTs) on electrically conducting substrates is mostly needed.…”

“…Email address: hongnt@htd.vast.vn https//doi.org/ 10.25073/2588-1124/vnumap.4477 method to transform the catalyst into the substrate are also important to the success of the VACNT growth. Using suitable catalysts along with CVD methods, some scientific groups have achieved good productions of the VACNTs [1,[2][3][4][5][6].…”

Carbon Nanotube Field Emitters Synthesized on Metal Alloy Substrate by PECVD for Customized Compact Field Emission Devices to Be Used in X-Ray Source Applications

“…Li et al synthesized CNTs on a metal alloy substrate by coating its surface with Ni before synthesis. Given that catalyst seeds, such as Ni, Cr, Fe, Co, and Mo, are needed for the nucleation of CNTs, many reports emphasize the direct growth of CNTs on metal alloy substrates such as alloys of Ni, Fe, and the Cr (NFC alloy) system [ 7 , 8 , 9 , 10 , 11 ]. By using these metal alloy substrates (with or without surface modification), separate processes involving the sputtering of the above mentioned active catalysts and/or reagents, such as HNO 3 and HCl, can be avoided.…”