Enhanced Field Emission of Single-Wall Carbon Nanotube Cathode Prepared by Screen Printing with a Silver Paste Buffer Layer.

Ruirui Jiang,Jing Zhao,Kaiqiang Yang,Baoqing Zeng,Jianlong Liu

doi:10.3390/nano12010165

Abstract

A high emission current with relatively low operating voltage is critical for field emission cathodes in vacuum electronic devices (VEDs). This paper studied the field emission performance of single-wall carbon nanotube (SWCNT) cold cathodes prepared by screen printing with a silver paste buffer layer. The buffer layer can both enforce the adhesion between the SWCNTs and substrate, and decrease their contact resistance, so as to increase emission current. Compared with paste mixing CNTs and screen printed cathodes, the buffer layer can avoid excessive wrapping of CNTs in the silver slurry and increase effective emission area to reduce the operating voltage. The experimental results show that the turn-on field of the screen-printed SWCNT cathodes is 0.9 V/μm, which is lower than that of electrophoretic SWCNT cathodes at 2.0 V/μm. Meanwhile, the maximum emission current of the screen-printed SWCNT cathodes reaches 5.55 mA at DC mode and reaches 10.4 mA at pulse mode, which is an order magnitude higher than that of electrophoretic SWCNTs emitters. This study also shows the application insight of small or medium-power VEDs.

Highlights

Field emission cathodes are an ideal type of electron source for vacuum electronic devices (VEDs), which have the characteristics of radiation resistance, fast start-up, room temperature working, small size, and low cost [1]
single-wall carbon nanotube (SWCNT) cold cathodes with a silver paste buffer layer were prepared by screen printing
The experimental results show that the turn-on field of the SWCNT cathode as cathode

Summary

Introduction

Field emission cathodes are an ideal type of electron source for vacuum electronic devices (VEDs), which have the characteristics of radiation resistance, fast start-up, room temperature working, small size, and low cost [1]. The low stability at a high emission current is a key technical problem for field emission cathodes to be used in VEDs [5]. As early as 2000, Spindt et al successfully developed a C-band traveling wave tube (TWT) with a Spindt-type field emission array cathode with a maximum emission current of 91.4 mA and the corresponding current density was 11.5 A/cm2 [4]. They increased the emission current to 121 mA, and the maximum emission current density reached 15.4 A/cm2 [8]. The thin-film field emission cathodes, such as carbon nanotube (CNT)

Methods

Results

Conclusion