Integration of carbon nanotubes into diluted magnetic semiconductor

Carbon nanotubes (CNTs) were grown using catalytic pyrolysis of acetylene on a thin-film-diluted magnetic semiconductor (Co-8 at. % doped Ti O2) without consuming the host layer of semiconductor Ti O2. Effects of the thickness of the diluted magnetic semiconductor layer and the stacking structure on the growth of the carbon nanotubes were examined. The external diameter and crystalline structure of the nanotubes showed correlation with the structure of the magnetic catalyst Co within the nanotubes or at the end of the tube. After the growth of CNTs, the Ti O2 layer still maintained its semiconducting properties in view of the temperature dependent resistance behavior. Moreover, we studied the influence of the electrical resistivity, i.e, the thickness as a process parameter, of the diluted magnetic semiconductor underlayer, which determines the growth height and the crystalline quality of the carbon nanotubes, on the nanotubes' growth behavior. Finally, we measured the magnetic behavior of the heterosystem and interpreted the results due to the action of the properties of the catalytic diluted magnetic semiconductor underlayer. Our result shows a promising recipe for the fabrication of one-dimensional CNT-two-dimensional magnetic-metal-doped magnetic semiconductor and/or wide-band-gap insulator.