Abstract

Metal-carbon nanotube (CNT) hybrid conductors aim to combine the high conductivity of traditional metals with the low mass and temperature coefficient of resistance (TCR) of carbon nanotubes. The high conductivity of copper makes it a promising candidate to combine with CNTs in a hybrid structure, but there is limited physical and electrical interaction between copper and CNTs. The use of an interfacial layer offers one method of improving the interconnection of a Cu-CNT hybrid conductor. In this dissertation, a joule heating-driven chemical vapor deposition (CVD) technique is developed to deposit nanometal seeds throughout a porous, low-density (0.12 g/cm3, ~9 mg/m) CNT roving template. Modification of the applied current to the CNT roving allows for the tuning of depositions towards either hot-spot site-specificity or overall uniformity. The effects of temperature, pressure, precursor mass, and the interval of applied current are investigated, demonstrating nanometal depositions ranging from less than 5 % w/w to over 85 % w/w. The versatility of CVD allows for a wide variety of metals to be deposited including copper, nickel, silver, tungsten, palladium, platinum, ruthenium, rhodium, and iridium. In particular, platinum acetylacetonate [Pt(acac)2] deposits with enhanced adhesion to the CNT roving and exhibits smaller nanometal seed diameters of 5 nm compared to 40 nm for copper. The Pt(acac)2 depositions also lead to improvements in the resistance of seeded CNTs across all mass loadings studied, with the largest improvements to the specific conductivity measured with 20-50 % w/w platinum seeds. CVD seeded CNT conductors with ~30 % w/w platinum are electroplated with copper, densified, and annealed produce Cu-CNT hybrid conductors with specific conductivities as high as 5772 S·m2/kg and TCR (from 300–600 K) as low as 2.74 × 10 3 K 1, indicating good interconnection of the metal and CNT portions. Room temperature electrical conductivities of 29.8 MS/m are achieved, comparable to traditional metallic electrical conductors like aluminum and copper. High conductivity, low TCR electrical conductors such as the nanometal interconnected Cu-CNT hybrids have numerous future applications towards high efficiency motors, generators, and transformers.

Library of Congress Subject Headings

Carbon nanotubes--Electric properties; Electric conductors; Chemical vapor deposition; Copper plating

Publication Date

8-10-2020

Document Type

Dissertation

Student Type

Graduate

Degree Name

Microsystems Engineering (Ph.D.)

Department, Program, or Center

Microsystems Engineering (KGCOE)

Advisor

Brian J. Landi

Advisor/Committee Member

Parsian K. Mohseni

Advisor/Committee Member

Ivan Puchades

Campus

RIT – Main Campus

Plan Codes

MCSE-PHD

Download

Share

COinS