A method to grow regular arrays of oriented carbon nanotubes on silicon substrates is presented. It has been found that porous silicon is an ideal substrate for growing self-oriented carbon nanotubes on large surfaces. The growth mechanism of nanotube arrays has been discussed. The potential applications of carbon nanotube arrays in flat panel display and in synthesizing of other semiconducting nanorods on silicon substrates through the carbon nanotube-confined reaction have also been studied. (C) 2000 Elsevier Science B.V. All rights reserved.