Improving carbon nanotube/copper film composite electrical performances by tailoring oxygen interface through gaseous ozone treatment of carbon nanotube films

Abstract

We experimentally establish for the first time the influence of oxygen at carbon nanotube (CNT)-Cu interface on CNT/Cu composite electrical performances. We fabricated CNT/Cu films (CCF) with systematically varied oxygen interface characteristics through Cu electron beam deposition of CNT films functionalized by O3(g) exposure. By altering O3(g) exposure times (30–1000 s), different contents and types of interfacial O-functionalities (sp3C-O and sp2CO) were obtained. CCF with optimal interfacial oxygen type and content showed enhanced CNT-Cu wetting and improvement in 4-probe electrical conductivities and their temperature stability. For e.g., Cu/CNT with interface sp3C-O and sp2CO and O:C at% ratio ~4.6 × 10–1 showed 1.6 × and 1.8 × higher electrical conductivity at room temperature and 110 °C, respectively than composites with only sp3C-O interface and O:C at% ratio ~2.7 × 10–1. Favorable effects of interfacial oxygen in previous literature have chiefly focused on CNT/Cu mechanical performances. Systematic studies on electrical performances vs. interfacial oxygen content and type are absent. Our results fill this knowledge-gap and provide experimental evidence on benefits of optimally tailored interfacial oxygen functionalities for enhancing Cu-nanotube interactions and composite electrical performances. We believe our work will add to existing CNT/Cu interface tailoring toolkits in literature, aiding fabrication and application-development of lightweight composites with rivaling performances.