The present invention is directed toward methods of attaching or grafting carbon nanotubes (CNTs) to silicon or other surfaces, wherein such attaching or grafting occurs via functional groups on either or both of the CNTs and silicon surface. The present invention is also directed to the novel compositions produced by such methods. Previous work by Applicants has demonstrated covalent attachment of arenes via aryldiazonium salts to Si (hydride passivated single crystal or poly Si; or , p-doped, n-doped or intrinsic), GaAs, and Pd surfaces. In the case of Si, this provides a direct arene-Si bond with no intervening oxide. Applicants have also reported on the use of aryldiazonium salts for the direct covalent linkage of arenes to single wall carbon nanotubes (SWNTs) where the nanotubes can exist either as bundles or individual structures (when surfactant-wrapped). In some embodiments, the present invention is directed to a merger of these two technologies to afford the covalent attachment of individualized (unroped) SWNTs to Si surfaces.