Chang Ting-Hsun, Kunuku Srinivasu, Kurian Joji, Manekkathodi Afsal, Chen Lih-Juann, Leou Keh-Chyang, Tai Nyan-Hwa, Lin I-Nan
†Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu 300, Taiwan, R.O.C.
§Department of Engineering and System Science, National Tsing-Hua University, Hsinchu 300, Taiwan, R.O.C.
ACS Appl Mater Interfaces. 2015 Apr 15;7(14):7732-40. doi: 10.1021/acsami.5b00844. Epub 2015 Mar 31.
We improved the electron field emission properties of ultrananocrystalline diamond (UNCD) films grown on Si-tip arrays by using the carbon nanotubes (CNTs) as interlayer and post-treating the films in CH4/Ar/H2 plasma. The use of CNTs interlayer effectively suppresses the presence of amorphous carbon in the diamond-to-Si interface that enhances the transport of electrons from Si, across the interface, to diamond. The post-treatment process results in hybrid-granular-structured diamond (HiD) films via the induction of the coalescence of the ultrasmall grains in these films that enhanced the conductivity of the films. All these factors contribute toward the enhancement of the electron field emission (EFE) process for the HiDCNT/Si-tip emitters, with low turn-on field of E0 = 2.98 V/μm and a large current density of 1.68 mA/cm(2) at an applied field of 5.0 V/μm. The EFE lifetime stability under an operation current of 6.5 μA was improved substantially to τHiD/CNT/Si-tip = 365 min. Interestingly, these HiDCNT/Si-tip materials also show enhanced plasma illumination behavior, as well as improved robustness against plasma ion bombardment when they are used as the cathode for microplasma devices. The study concludes that the use of CNT interlayers not only increase the potential of these materials as good EFE emitters, but also prove themselves to be good microplasma devices with improved performance.
我们通过使用碳纳米管（CNT）作为中间层，并在CH4/Ar/H2等离子体中对在硅尖阵列上生长的超纳米晶金刚石（UNCD）薄膜进行后处理，改善了其电子场发射性能。使用CNT中间层有效地抑制了金刚石与硅界面处非晶碳的存在，这增强了电子从硅穿过界面传输到金刚石的能力。后处理过程通过诱导这些薄膜中超小晶粒的聚结，形成了混合颗粒结构的金刚石（HiD）薄膜，从而提高了薄膜的导电性。所有这些因素都有助于增强HiDCNT/硅尖发射器的电子场发射（EFE）过程，其开启场强低至E0 = 2.98 V/μm，在5.0 V/μm的外加场强下电流密度高达1.68 mA/cm²。在6.5 μA的工作电流下，EFE寿命稳定性大幅提高至τHiD/CNT/硅尖 = 365分钟。有趣的是，当这些HiDCNT/硅尖材料用作微等离子体器件的阴极时，它们还表现出增强的等离子体照明行为，以及对等离子体离子轰击的更强鲁棒性。该研究得出结论，使用CNT中间层不仅增加了这些材料作为良好EFE发射器的潜力，而且证明它们本身是性能得到改善的良好微等离子体器件。
