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<p>Carbon nanotubes (CNTs) have emerged as promising candidates for next-generation cold cathode electron sources due to their excellent field emission properties. However, the mechanism by which substrate materials influence emission performance remains poorly understood. In this work, we systematically investigate the field emission behavior of CNTs grown on stainless steel (SS304) and silicon (Si) substrates by combining experimental characterization with finite element simulations. The results show that the SS304 substrate, owing to its high electrical conductivity, significantly reduces contact resistance, enabling an ultralow turn-on field of 1.86&#xa0;V/µm and high current density of 5.5&#xa0;mA/cm<sup>2</sup>, thereby greatly enhancing emission efficiency. In contrast, although the Si substrate has lower electrical conductivity, its high thermal conductivity ranging from 140 to 150&#xa0;W/(m·K) allows for effective heat dissipation, resulting in excellent long-term stability with only 7% current fluctuation over a 4&#xa0;h period, which is significantly better than the 15% fluctuation observed for the SS304 based cathode. Triode structured electron gun tests further confirm the superior output performance of the SS304 based device under low driving voltages. Our results reveal a key trade-off between emission efficiency and thermal stability governed by substrate properties, providing valuable guidance for optimal substrate selection in the development of high performance and reliable carbon nanotube based vacuum electronic devices.</p> Graphical Abstract <p></p>

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Unveiling the Substrate Effect: A Combined Experimental and Simulation Study of Field Emission from Carbon Nanotubes on Stainless Steel and Silicon

  • 期刊论文

  • 发表日期：

    2026年2月21日

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  • Jianwei Chen,
  • Yike Zhao,
  • Yajie Guo,
  • Wuwei Feng,
  • Jiajie Fan,
  • Yangyang Zhao,
  • Jun Jiang

摘要

Carbon nanotubes (CNTs) have emerged as promising candidates for next-generation cold cathode electron sources due to their excellent field emission properties. However, the mechanism by which substrate materials influence emission performance remains poorly understood. In this work, we systematically investigate the field emission behavior of CNTs grown on stainless steel (SS304) and silicon (Si) substrates by combining experimental characterization with finite element simulations. The results show that the SS304 substrate, owing to its high electrical conductivity, significantly reduces contact resistance, enabling an ultralow turn-on field of 1.86 V/µm and high current density of 5.5 mA/cm2, thereby greatly enhancing emission efficiency. In contrast, although the Si substrate has lower electrical conductivity, its high thermal conductivity ranging from 140 to 150 W/(m·K) allows for effective heat dissipation, resulting in excellent long-term stability with only 7% current fluctuation over a 4 h period, which is significantly better than the 15% fluctuation observed for the SS304 based cathode. Triode structured electron gun tests further confirm the superior output performance of the SS304 based device under low driving voltages. Our results reveal a key trade-off between emission efficiency and thermal stability governed by substrate properties, providing valuable guidance for optimal substrate selection in the development of high performance and reliable carbon nanotube based vacuum electronic devices.

Graphical Abstract