Electrically conductive aluminum oxide thin film used as cobalt catalyst-support layer in vertically aligned carbon nanotube growth

Abstract

This paper will present the unique characteristics of aluminum oxide (Al-O) and cobalt catalyst included in aligned carbon nanotube (CNT) electrode system of energy storage device, namely electrochemical capacitor. Electrical conductivity and nanostructure of the thermally oxidized Al-O used as catalyst-support layer in vertically grown single-walled CNTs were studied. Al-O films were characterized by means of current-voltage measurement and high resolution transmission electron microscopy analysis. The Al-O support layer was found to be conductive, with a relatively low resistance and, approximately 20 nm film thickness of Al-O is suggested to be too thin to form insulating barrier. The scanning TEM-annular dark field analysis confirmed that the nanosized cobalt catalyst particles distributed on Al-O surfaces and also embedded inside the Al-O film structure.