A method for growing an array of carbon nanotubes includes the steps of: (a) providing a substrate having a first surface and a second surface opposite to the first surface; (b) forming a catalyst film on the first surface of the substrate; (c) flowing a mixture of a carrier gas and a carbon source gas over the catalyst film; (d) providing a semiconductor laser system to generate a focused laser beam; and (e) irradiating the focused laser beam on the substrate to grow an array of carbon nanotubes on the substrate.