Optimizing field-emission devices: Advancements in stability and performance with well-oriented and dense integrated carbon nanotube assemblies

Abstract

Carbon nanotubes (CNTs) are attracting widespread interest as electron emitters due to their superior field emission properties. However, the correlation between the microstructural properties of CNTs and their electron emission performance has not been fully understood, limiting the optimization of their performance particularly in terms of device stability. Herein, we present highly oriented and densely integrated CNT assemblies as a cold cathode material with stable field electron emission. These assemblies were prepared via the floating catalyst chemical vapor deposition-based direct spinning method, constructing a fibrous structure with a hierarchical composition of individual CNTs and bundles within the microstructure. By varying the spinning rate during the winding process, we engineered the microstructure of the CNT assemblies. The CNT assemblies spun at high rates presented a relatively higher degree of orientation and packing density for both individual CNTs and bundles, thus resulting in a thermally and mechanically stable microstructure. Furthermore, the stable microstructure of these CNT assemblies translated into an almost consistent electric field under repeated electron emission cycles, well-revealing their impressive stability in field electron emission. Overall, the CNT assemblies with a stable microstructure enable efficient and stable field electron emission, offering a promising strategy for devising CNT-based field electron-emitting devices.