Liu Jiayu Alexander, Wang Jiaqi, Cheraghi Elahe, Chen Siyuan, Sun Yonghai, Yeow John T W
Department of System Design Engineering, Advanced Micro-/Nano-Devices Lab, University of Waterloo, 200 University Ave. W., Waterloo, ON, N2L 3G1, Canada.
Nanoscale. 2022 Oct 27;14(41):15364-15372. doi: 10.1039/d2nr04205c.
In this paper, we present two methods to improve the field emission (FE) performance of vertically aligned carbon nanotube emitters that are treated with dimethyl sulfoxide (DMSO) solution and poly(3,4-ethylene dioxythiophene):polystyrene sulfonate (PEDOT:PSS) solution, respectively, and compared their performances. Both treatments force CNTs to be bundled into clusters, but the formed structures are very different. After treatment, both methods reduced the threshold electric field due to the reduction in screening effects, whereas the PEDOT:PSS treatment significantly reduced the threshold field to far lower than that of DMSO treatment. In addition, the FE efficiency and lifetime of treated CNT emitters are significantly improved. For both treated emitters, there is only slight degradation of the emission current after 80 hours of continuous FE at around 50 μA. In addition, the uniformity of both treated CNT emitters is improved which enables more CNTs to contribute to the overall current emission. This, in turn, lowers the current emitted by individual CNTs, and thereby increases the lifetime of the emitters. Therefore, this study demonstrates that these simple treatment methods of bundling CNTs into unique cluster-structures significantly improve the lifetime of FE and make them excellent candidates for large currents and long-term FE.
在本文中，我们分别介绍了两种用于改善垂直排列的碳纳米管发射体场发射（FE）性能的方法，这两种发射体分别用二甲基亚砜（DMSO）溶液和聚（3,4-亚乙基二氧噻吩）：聚苯乙烯磺酸盐（PEDOT:PSS）溶液进行处理，并比较了它们的性能。两种处理方法都会迫使碳纳米管聚集成束，但形成的结构差异很大。处理后，由于屏蔽效应的降低，两种方法都降低了阈值电场，而PEDOT:PSS处理显著降低了阈值电场，使其远低于DMSO处理后的阈值电场。此外，经处理的碳纳米管发射体的场发射效率和寿命也得到了显著提高。对于两种经处理的发射体，在约50 μA的连续场发射80小时后，发射电流仅有轻微下降。此外，两种经处理的碳纳米管发射体的均匀性都得到了改善，这使得更多的碳纳米管能够对总电流发射做出贡献。反过来，这又降低了单个碳纳米管发射的电流，从而延长了发射体的寿命。因此，本研究表明，这些将碳纳米管聚集成独特簇状结构的简单处理方法显著提高了场发射的寿命，使其成为大电流和长期场发射的理想候选材料。
