Vertically-Aligned Single-Crystal Nanocone Arrays: Controlled Fabrication and Enhanced Field Emission

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• 作者：Jing Lai Duan ; Dang Yuan Lei ; Fei Chen ; Shu Ping Lau ; William I. Milne ; M. E. Toimil-Molares ; Christina Trautmann ; Jie Liu
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：January 13, 2016
• 年：2016
• 卷：8
• 期：1
• 页码：472-479
• 全文大小：492K
• ISSN：1944-8252

文摘

Metal nanostructures with conical shape, vertical alignment, large ratio of cone height and curvature radius at the apex, controlled cone angle, and single-crystal structure are ideal candidates for enhancing field electron-emission efficiency with additional merits, such as good mechanical and thermal stability. However, fabrication of such nanostructures possessing all these features is challenging. Here, we report on the controlled fabrication of large scale, vertically aligned, and mechanically self-supported single-crystal Cu nanocones with controlled cone angle and enhanced field emission. The Cu nanocones were fabricated by ion-track templates in combination with electrochemical deposition. Their cone angle is controlled in the range from 0.3° to 6.2° by asymmetrically selective etching of the ion tracks and the minimum tip curvature diameter reaches down to 6 nm. The field emission measurements show that the turn-on electric field of the Cu nanocone field emitters can be as low as 1.9 V/μm at current density of 10 μA/cm² (a record low value for Cu nanostructures, to the best of our knowledge). The maximum field enhancement factor we measured was as large as 6068, indicating that the Cu nanocones are promising candidates for field emission applications.