Abbas Sayed Zafar, Lee Jaehwi, Mehdi Syed Muhammad Zain, Cho Jaewon, Raza Ahmed, Kim Sungkyu, Goak Jeung Choon, Lee Naesung
Department of Nanotechnology and Advanced Materials Engineering, Hybrid Materials Centre (HMC), Sejong University, Seoul, 05006, Republic of Korea.
Graduate School of Optical Engineering, Sejong University, Seoul, 05006, Republic of Korea.
Small. 2025 Aug;21(32):e2500242. doi: 10.1002/smll.202500242. Epub 2025 Jun 13.
Carbon nanotube field emitters (CNT FEs) have obtained increasing attention for vacuum electronics devices such as cold cathode X-ray tubes. However, the low adhesion of CNTs on the substrate thwarts their ability to achieve high field emission current density. To this end, the effects of Ni, Si, and AlO fillers on their adhesion both in the paste and onto the Kovar (nickel-cobalt ferrous alloy) substrate are investigated. Chemical reactions between Ni, Si, and the Kovar constituents lead to the formation of micrometer-sized protruding particles. Si fillers are key in promoting their formation in the paste and on the substrate. During high-temperature vacuum annealing, the Si fillers reacted with the Ni fillers and the Kovar constituents, forming NiSi in the paste and FeNiSi on the substrate, both of which strengthened adhesion. The adhesion of CNT FEs with both Ni and Si fillers is better compared to those containing Ni or Si fillers alone. With the resulting retention of more CNTs on the substrate after tape activation, a current density of 30.9 A cm and stable field emission for 14 h at 500 mA cm are achieved, indicating the commercial potential of CNT FEs in vacuum electronics.
碳纳米管场发射体（CNT FE）在诸如冷阴极X射线管等真空电子器件中受到越来越多的关注。然而，碳纳米管在基底上的低附着力阻碍了它们实现高场发射电流密度的能力。为此，研究了镍、硅和氧化铝填料对其在浆料中以及在可伐合金（镍钴铁合金）基底上附着力的影响。镍、硅与可伐合金成分之间的化学反应导致形成微米级的突出颗粒。硅填料是促进它们在浆料中和基底上形成的关键。在高温真空退火过程中，硅填料与镍填料和可伐合金成分发生反应，在浆料中形成NiSi，在基底上形成FeNiSi，两者都增强了附着力。与仅含镍或硅填料的碳纳米管场发射体相比，含镍和硅填料的碳纳米管场发射体的附着力更好。通过胶带激活后在基底上保留更多的碳纳米管，实现了30.9 A/cm²的电流密度以及在500 mA/cm²下14小时的稳定场发射，这表明碳纳米管场发射体在真空电子学中的商业潜力。
