Experimental Study On Improving The Contact Resistance Of Carbon Nanomaterials By Doping

As a typical representative of advanced carbon nanomaterials,carbon nanotubes(CNTs)have been used to build various nanodevices owing to their unique structure and excellent properties.However,the high contact resistance between CNTs and metal electrodes after CNTs' assembly will cause a large amount of joule heat in the contact area,which greatly limits the practical application of CNTs in micro-/nano-electronics.Based on the formation mechanism of contact resistance between CNTs and metals,doping on CNTs can be employed to improve the contact resistance effectively.The electroless deposition method has been used to dope CNTs with transition metals gold and palladium.For doping CNTs with gold,the nitric acid reflux oxidized CNTs were well dispersed,and the CNT dispersion was dropped into the gold sol solution to produce the samples of gold nanoparticle-doped CNTs by oscillating deposition.For doping CNTs with palladium,the mixed acid oxidized CNTs were well dispersed,and the CNT dispersion was immersed into an electroless deposition solution of palladium,and then subjected to ultrasonication,resting and stirring sequentially to obtain the sample of palladium nanoparticle-doped CNTs.Dielectrophoresis method was then used to assemble the original and doped CNTs respectively between the gold electrodes,and the contact resistance of CNTs was measured in real time.The results show that defects and oxygen-containing functional groups have been made by nitric acid reflux and mixed acid oxidation on the surface of CNTs.The electroless deposition method successfully incorporates gold and palladium nanoparticles into the CNT wall with the atomic percentage of 0.24% and 19.75% respectively,and the doping types are both P-type.Compared with the original CNTs,the contact resistances of the gold-doped CNT samples and palladium-doped CNT samples with electrodes are respectively reduced by 71.49% and 71.09%.The contact resistance between CNTs and metal electrodes can be effectively improved by doping gold and palladium,which will provide guidance for the application of advanced carbon nanomaterials such as CNTs in micro-/nano-electronics and other fields.Figure 33;Table 10;Reference 106.