Metal nanofibrils embedded in long free-standing carbon nanotube fibers with a high critical current density

Abstract

With the growth of nanoelectronics, the importance of thermal management in device packaging and the improvement of high-current-carrying interconnects/wires for avoiding the premature failure of devices have been emphasized. The heat and electrical transport properties of the bulk may not be valid in the characterization of a material at the nanometer level, because the phenomena that occur at the interfaces and grain boundaries become dominant. The failure mechanism of bulk metal interconnects has been understood in the context of electromigration; however, in nanoscale materials, the effect of the heat dissipation that occurs at the nanointerfaces may play an important role. Here, we report the preparation of continuous carbon nanotube (CNT)-Cu composite fibers that possess Cu nanofibrillar structures with a high current-carrying capacity. Various-shaped CNT-Cu microfibers with different Cu grain morphologies were produced via Cu electroplating on continuous CNT fibers. Cu fibril structures were embedded in the voids inside the CNT fiber during the early stage of electrodeposition. The temperaturedependent and magnetic field-dependent electrical properties and the ampacity of the produced CNT-Cu microfibers were measured, and the failure mechanism of the fiber was discussed. The interconnection of Cu nanograins on the surface of the individual CNTs contributed to the enhancement in the charge-carrying ability of the fiber. The effective ampacity of the Cu nanofibrils was estimated to be~1 × 10 7 A/cm 2 , which is approximately 50 times larger than the ampacity measured for a bulk Cu microwire.

Corrosion behaviour of cast and deformed copper-carbon nanotube composite wires in chloride media

“…Grujicic et al (2002) have shown that smaller copper concentration leads to smaller and densely distributed nuclei. A similar observation of the grain size of copper on the inside of CNT macrostructures and on the cladding been reported for electrodeposited CNT-Cu by many authors (Yang et al, 2008;Sundaram et al, 2017aSundaram et al, , 2017bChen et al, 2018a;Rho et al, 2018). In Figure 20, the deposition current used in creating 3.5 cm long CNT-Cu fibers (D =~10 μm) is plotted against the recorded stable electrode potential (V vs. Cu/CuSO4 reference electrode) during deposition and the time (s) it took to fully cover the surface of the fiber with copper.…”

“…To the author's knowledge, the first to report increased electromigration resistance, i.e., ampacity, were Chai et al (2008b), for nanotubes vertically embedded inside a Cu matrix. Since then, several authors (Subramaniam et al, 2013(Subramaniam et al, , 2014Shuai et al, 2016;Sundaram et al, 2017aSundaram et al, , 2018Kim et al, 2018;Rho et al, 2018;Zou et al, 2018) have reported increased ampacity of their CNT-Cu (or graphene-Cu) composites, compared against a copper reference sample in the same set-up. The improvement has been observed for various types of CNT-Cu configurations with both Cu cladding on CNT material and CNTs embedded inside a Cu matrix, with the property measured both perpendicular and parallel to the nanotube alignment.…”

An Axially Continuous Graphene–Copper Wire for High‐Power Transmission: Thermoelectrical Characterization and Mechanisms

“…With the increasing use of modern electric power systems in the aerospace and transportation industries, and the progressive miniaturization of advanced electronic and communication devices, current‐carrying capability and environmental stability of conductors are becoming critical issues. [ 1–4 ] Therefore, there is high demand for more effective material systems to replace traditional metal wires such as copper (Cu) and aluminum (Al) that have been widely used in the past due to their excellent electrical conductivity.…”

Materials and Structural Designs for Neural Interfaces

“…The laser pyrolysis method for 3D graphene allows it to efficiently fabricate a manufactured large area, as shown in Figure a. Using this device, they reported the in vivo neural recording experiments performed on rat models. , The low impedance (2 kΩ to 8 kΩ), high CIC (3.1 mC/cm 2 ), and flexibility made the electrodes appropriate for cortical recording and stimulation, showing a high SNR recording on low-amplitude evoked potentials from the rat’s somatosensory cortex.…”