Abstract
Abstract In this work, the influences of sequence of the deposited thin films (Al, Fe and Mo), which were coated onto SiO2/Si substrates for forming multi-layer catalyst system, on the growth of single-walled carbon nanotubes (SWNTs) were studied. Experimental results showed that different morphologies and number of SWNTs were obtained when different catalyst systems were adopted. The feasible mechanism of the Al-Fe-Mo catalyst system for growing SWNTs wsa discussed. Besides, Al-Fe-Mo catalyst system was also deposited on different substrates (sapphire, MgO and AlN), and difference of the synthesized CNTs on these substrates was discussed. The result shows that Al-Fe-Mo catalyst system was suitable for sapphire and MgO substrates for grown SWNTs. Growth of the bridging SWNTs using Al-Fe-Mo catalyst system is also studied. In this study, the bridging SWNTs were synthesized successfully by covering insulated layer (MgO) on catalyst. By controlling the growth of SWNTs grown in the lateral direction, bridging SWNTs connecting catalyst pads were made. This work also found that a proper ratio of insulated layer to catalyst layer is required for obtaining bridging SWNTs.