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Enhanced Field Emission from a Carbon Nanotube Array Coated with a Hexagonal Boron Nitride Thin Film
Author(s) -
Yang Xiaoxia,
Li Zhenjun,
He Feng,
Liu Mingju,
Bai Bing,
Liu Wei,
Qiu Xiaohui,
Zhou Hang,
Li Chi,
Dai Qing
Publication year - 2015
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201403323
Subject(s) - hexagonal boron nitride , materials science , carbon nanotube , field electron emission , thin film , boron nitride , nanotechnology , hexagonal crystal system , nitride , optoelectronics , chemical engineering , graphene , crystallography , layer (electronics) , chemistry , physics , quantum mechanics , electron , engineering
A high‐quality field emission electron source made of a highly ordered array of carbon nanotubes (CNTs) coated with a thin film of hexagonal boron nitride ( h ‐BN) is fabricated using a simple and scalable method. This method offers the benefit of reproducibility, as well as the simplicity, safety, and low cost inherent in using B 2 O 3 as the boron precursor. Results measured using h ‐BN‐coated CNT arrays are compared with uncoated control arrays. The optimal thickness of the h ‐BN film is found to be 3 nm. As a result of the incorporation of h ‐BN, the turn‐on field is found to decrease from 4.11 to 1.36 V μm −1 , which can be explained by the significantly lower emission barrier that is achieved due to the negative electron affinity of h ‐BN. Meanwhile, the total emission current is observed to increase from 1.6 to 3.7 mA, due to a mechanism that limits the self‐current of any individual emitting tip. This phenomenon also leads to improved emission stability and uniformity. In addition, the lifetime of the arrays is improved as well. The h ‐BN‐coated CNT array‐based field emitters proposed in this work may open new paths for the development of future high‐performance vacuum electronic devices.