Abstract: A method of vertically aligning pure carbon nanotubes on a large glass or silicon substrate at a low temperature using a low pressure DC thermal chemical vapor deposition method is provided. In this method, catalytic decomposition with respect to hydro-carbon gases is performed in two steps. Basically, an existing thermal chemical vapor deposition method using hydro-carbon gases such as acetylene, ethylene, methane or propane is used. To be more specific, the hydro-carbon gases are primarily decomposed at a low temperature of 400-500° C. by passing the hydro-carbon gases through a mesh-structure catalyst which is made of Ni, Fe, Co, Y, Pd, Pt, Au or an alloy of two or more of these materials.