The Technology Of Carbon Nanotubes Implanting Into Metal Electrode Surface And It's Application Research

Nanotubes have broad applications because of it's unique structure and property, which has caused academic circles and industrial circles's high attenation to carried out wide researches, especially in the fabrication of field emission cathode and sensitive Electrode. All of those devices'good properties need a good connection between CNTs and metal electrode, so research a novel method of embedding CNTs into metal electrode surface is very important.In all the fabricating methods of embedding CNT into metal surface, there are two typical types- direct growth and the screen printing. But each of them has certain disadvantages. For example, in screen printing, the density and heights of CNTs are random. In the direct growth, the length of CNT and the distance between the CNT tips cannot be accurately controlled; CNT is catalytically grown on the substrates, so the adhesion is often not strong enough; the high temperature condition (800–1000℃) which may damage substrates. In addition, direct growth and screen printing process would introduce impurities.In this paper, we have proposed a novel method named"planting technology"which is combined with micromachining technology to realize a good embedding between CNTs and metal substrate, actually controlling of CNTs'the density and heights, and all of process are happened in low temperature. Base on this technology, we have exploited got high property field emission cathode and sensitive Electrode. The main work and the conclusions of this dissertation are as follows:(1) polymer-matrix vertical planting technology of implanting CNTs into metal electrode surface.The structure which is part of CNT implanted into metal electrode surface and the other part of CNT exposed on the metal surface can be realize by vertical planting technology(VPA). Using photoresist as polymer, we build an integrated manufacturing process framework of CNT implanting metal surface. Pretreated CNTs are mixed with polymer into homogenate by ball grinder over two hours, and then the composite film is formed by spinning homogenate on the substrate; solidify and polish composite film, and chemical etch part of polymer from the surface of film in order to keep one end of the CNTs be inserted in polymer and the other end outside of polyimide; sputter conducting layer on the film surface and electroplate metal on the conducting layer to coat the outcrop of CNT; release the rest polymer.All experimental steps are completed at room temperature. Not only the process of planting technology is simple, but also it has combined the advantages of direct growth and screen printing, and eliminated their disadvantages.Base on planting technique, we propose reverse planting technology (RPT). PRT using the surface of CNT-polymer composite material which between the substrate and composite film as the base surface, the followed process like etching, sputtering and electroplate all happened on this surface. This surface can be got by etching off Si substrate. Using RPT, we can get more smoothly device's surface.(2) The application of vertical planting technique on field emission cathodeIn this chapter, the influences of key technological parameters on field emission property are being discussed. The key parameters include the weight ratio between CNT and photoresist, ball milling time, etching time, degassing technology,the choice of CNT kind. After analysis, we get the proper weight ratio between CNT and photoresist is 1:10; the proper milling time is 12H; the proper etching time for photoresist is 15s.(3) The application of horizontal planting technique on sensitive electrode.Base on planting technology, we design a method to realize CNT lap joint on the two terminals of electrodes by micromachining to fabricate micro sensitive electrode, and to realize cross-scales sensitive electrode manufacture. We named this technology as"horizontal planting technology". We design different process to fabricate sensitive electrode according using different polymer as medium, and related advantages and disadvantages are be discussed. Through observation by SEM, we can see the CNT lap joint on the two terminals of electrodes, and through testing the device's real-time resistance, we can find under outside sensitive conditions,the devices show a certain degree of sensitivity characteristics, in the more, it give a good demonstration that the carbon nanotubes have a good connection with metal electrodesPlanting technology can realize CNT used in micromachining process. Through planting technology, many of micro devices can be manufactured which use CNT as key functional parts. The proposal of the fabrication process of these two devices makes the large scale integrated manufacture of CNT devices possible.