Vertical aligned carbon nanotubes were synthesized on quartz glass and Au film by catalytic decompositon of ferrocene and xylene. Morphological differences between aligned nanotubes grown on the two substrates are studied and discussed through SEM images. Field emission testing shows that aligned nanotubes grown on Au have a lower threshold field than those grown on quartz glass. This reduction of threshold field indicates a new way to improve field emission properties through the selection of a highly conductive growth substrate for carbon nanotubes.