Experimental Results of Carbon Nanotube Fabrication via CVD with Iron Catalyst and Acetylene Precursor

Carbon nanotubes (CNTs) grow in forests varying in correspondence to many factors. Forests of CNTs have been fabricated via catalytic chemical vapor deposition (CCVD) in a quartz tube furnace of dimensions 6\u27\u27 diameter x 51\u27\u27 length. The general conditions inside the furnace were: 750°C synthesis temperature, -0.06MPa to -0.01MPa relative to atmospheric pressure, and two major gas compositions C2H2 and H2 (Ar for safety protocol). Acetylene (24-96sccm) was used as a precursor in conjunction with hydrogen gas (24-36sccm) as an etchant; Ar was kept at a constant 36sccm. The various catalysts tested were aluminum-iron-aluminum multilayered thin films with and without photoresist, 800nm iron nanoparticles spun on, 0.4nm to .5nm iron via physical vapor deposition (PVD). We have attempted growth on silicon wafers with a SiO2, Al2O3, or AZO oxide layer (to prevent diffusion of catalyst into substrate) and have had the most success from SiO2. The documentation of CNT forests is aided by the Hitachi S-3000N HR Scanning Electron Microscope. CNTs varied in growth densities of small bundles to forests. Growth of forests tended to occur at the edge of patterned catalysts