Field emission from the composite structure of silicon tips and vertical carbon nanotubes

The composite structure of silicon tips and vertical aligned carbon nanotubes (CNTs) was prepared using plasma enhanced hot filament chemical vapor deposition (PE-HFCVD) method on the silicon wafer, and Au/Ni film coated on the substrate was considered as a catalyst. High proportion hydrogen of 96% volume percentage and high total pressure are used during preparing process, and the pure CNTs, pure silicon tips, and the admixture of silicon tips and CNTs can be prepared by varying the total pressures, respectively. Scanning electron microscopy measurement shows that Si tips are formed in the vertical aligned CNTs, and the related formation mechanism of this admixture was discussed. The results of field emission measurement show that this composite structure has very excellent electron field emission properties - low threshold field, high emission current density and stable emission current, which are attributed to the increased field enhancement factor and reducing field shield effect for this composite structure.