A process for transferring carbon nanotube (CNT) arrays from a silicon wafer to an alumina substrate coated with Ag paste is proposed. A current density of up to 325 mA cm−2 at an electric field of 2.4 V µm−1 was achieved. The influence of the patterned size and the length of carbon nanotubes on the field emission properties were investigated. Through this transfer method, the adhesion between the CNTs and the substrate is enhanced and the current density and turn-on voltage are improved. The effects of the microstructure of the emitting sites at the CNT tip on the current density were also studied.

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Palladium nanostructures with variation in shape and size have been synthesized using an electrochemical deposition method. Cyclic voltammetry and linear sweep voltammetry have been used to study the growth of Pd nanoparticles on Si substrates and tungsten wire. Different sets of solutions containing PdCl 2 , Pd(NO 3 ) 2 , and PdSO 4, respectively, have been used to grow the Pd nanoparticles. Field emission scanning electron microscopy was used to visualize the Pd nanostructures on various substrates. The Pd nanostructures were used as a catalyst to grow the multiwall carbon nanotubes (MWCNT) by a microwave plasma enhanced chemical vapor deposition method. Dependence of the Pd nanoparticle shape on the architecture of MWCNTs is discussed. Carbon nanotubes were also grown on the tungsten tips. Development of Pd into Pd 2 Si during growth of MWCNT on Pd-coated Si has been studied. The nanotubes were observed to be filled by Pd 2 Si. Raman spectroscopy has been used to study the structure of the Pd 2 Si filled carbon nanotubes.

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A repeated growth process (regrowth process) has been carried out to fabricate a carbon nanotube (CNT) array without additional catalyst by a custom-made plasma-enhanced thermal chemical vapor deposition (PE-thermal CVD) technique. An Fe film with a thickness of 3 nm is coated as a catalyst before the first growth on the SiO 2 /Si by arc plasma deposition. Two types of treatments, lift-off and thermal annealing, are used to remove the CNTs away for the next growth. Thermal annealing is also used to remove amorphous carbon, which covers the catalytic nanoparticles and to activate the catalyst. The CNT array is regrown without coating additional catalyst through the regrowth process. After certain cycles, high-purity single-walled carbon nanotubes (SWNTs) are synthesized and the I D =I G ratio of the Raman spectrum reaches a low value of 0.41. The crystallization of CNTs is improved after each growth cycle of thermal annealing treatment.