【摘要】：碳納米材料具有多樣的結(jié)構(gòu)、優(yōu)異的物理和化學(xué)性質(zhì),近年來(lái)引起了廣泛的關(guān)注。其中,石墨烯和碳納米管由于獨(dú)特的結(jié)構(gòu)和優(yōu)異的性能,已經(jīng)成為了各個(gè)領(lǐng)域的研究熱點(diǎn),其中的一個(gè)潛在應(yīng)用就是作為場(chǎng)發(fā)射電子源。人們針對(duì)兩種材料的場(chǎng)致發(fā)射開(kāi)展了大量的研究工作,并取得了不錯(cuò)的進(jìn)展。本文針對(duì)石墨烯在場(chǎng)致發(fā)射應(yīng)用中出現(xiàn)的不足,使用不同方法制備了性能較好的石墨烯,并充分地突出了石墨烯作為場(chǎng)發(fā)射材料的結(jié)構(gòu)優(yōu)勢(shì)。除此之外,還探索并優(yōu)化了碳納米管的制備條件,同時(shí)提高了碳納米管的場(chǎng)發(fā)射性能。主要的研究?jī)?nèi)容如下:使用電泳沉積的方法在含有微孔的圖案化不銹鋼(SUS304)基底上制備了石墨烯發(fā)射體,并使用一定的方式進(jìn)行表面處理。這種三維石墨烯發(fā)射體的微孔內(nèi)含有較多直立排布的鋒利邊緣,其場(chǎng)發(fā)射性能相比平面基底上的石墨烯有了顯著的提高,不僅具有更低的開(kāi)啟和閾值電場(chǎng),其發(fā)射電流密度也提高了近十倍。這種設(shè)計(jì)為基于層狀結(jié)構(gòu)的冷陰極提供了更多的可能。使用等離子體增強(qiáng)化學(xué)氣相沉積方法在不同種類基底上成功制備了石墨烯墻,并深入研究了不同的生長(zhǎng)參數(shù)對(duì)石墨烯墻場(chǎng)發(fā)射性能的影響。石墨烯墻的形貌及微觀結(jié)構(gòu)也可以通過(guò)不同的生長(zhǎng)參數(shù)進(jìn)行調(diào)節(jié)。具有開(kāi)放邊緣的直立石墨烯墻表現(xiàn)出了很好的場(chǎng)發(fā)射性能。場(chǎng)發(fā)射測(cè)試之后盡管石墨烯墻的形貌改變較大,其場(chǎng)發(fā)射性能并沒(méi)有明顯衰減。使用等離子體增強(qiáng)化學(xué)氣相沉積技術(shù)在不同尺寸的六邊形圖案化Si基底上成功制備了直立碳納米管陣列。同時(shí)也在其他基底上進(jìn)行了制備,并通過(guò)改變不同的實(shí)驗(yàn)參數(shù)包括催化劑種類、過(guò)渡層以及H2/C2H2通入比例等對(duì)碳納米管生長(zhǎng)和場(chǎng)發(fā)射性能進(jìn)行了優(yōu)化。碳納米管發(fā)射體表現(xiàn)出了優(yōu)異的場(chǎng)發(fā)射性能,不僅具有較大的發(fā)射電流密度還具有很好的發(fā)射穩(wěn)定性。
[Abstract]:Carbon nanomaterials have attracted wide attention in recent years because of their diverse structures and excellent physical and chemical properties. Among them, graphene and carbon nanotubes (CNTs) have become a hot research field due to their unique structure and excellent properties. One of the potential applications is as a field emission electron source. A great deal of research work has been done on the field emission of two kinds of materials, and good progress has been made. In this paper, graphene with good properties has been prepared by different methods in allusion to the shortcomings in the field emission application of graphene, and the structural advantages of graphene as a field emission material have been fully highlighted. In addition, the preparation conditions of carbon nanotubes were explored and optimized, and the field emission properties of carbon nanotubes were improved. The main research contents are as follows: graphene emitters were prepared on patterned stainless steel (SUS304) substrates containing micropores by electrophoretic deposition and treated in a certain way. The three dimensional graphene emitters have many sharp edges arranged vertically in their micropores. The field emission performance of the three dimensional graphene emitters is significantly improved compared with that of the graphene on the planar substrate, and not only has a lower opening and threshold electric field. The emission current density has also increased by nearly ten times. This design provides more possibilities for cold cathode based on layered structure. Graphene walls were successfully prepared on different substrates by plasma enhanced chemical vapor deposition. The effects of different growth parameters on the field emission properties of graphene walls were studied. The morphology and microstructure of graphene wall can also be adjusted by different growth parameters. The vertical graphene wall with open edge exhibits good field emission performance. After field emission testing, the field emission properties of graphene wall did not decrease significantly, although the morphology of the wall changed greatly. The vertical carbon nanotube arrays were successfully fabricated on hexagonal patterned Si substrates by plasma enhanced chemical vapor deposition. At the same time, the growth and field emission properties of CNTs were optimized by changing different experimental parameters such as catalyst type, transition layer and H2/C2H2 input ratio. Carbon nanotubes (CNTs) emitters exhibit excellent field emission properties, not only with high emission current density, but also with good emission stability.
【學(xué)位授予單位】：燕山大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TB383.1;O613.71

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本文編號(hào)：2235975