Role of work function in field emission enhancement of Au island decorated vertically aligned ZnO nanotapers

Autor: Anil K. Sinha, Kartik Senapati, Mohit Kumar, Avanendra Singh, Tapobrata Som, Pratap K. Sahoo
Rok vydání: 2017
Předmět:
Zdroj: Applied Surface Science. 411:117-123
ISSN: 0169-4332
DOI: 10.1016/j.apsusc.2017.03.060
Popis: In this report, we demonstrate significantly enhanced field emission properties of ZnO nanotapers achieved via a corrugated decoration of Au. Field emission experiments on these Au-decorated ZnO nanotapers showed emission current densities comparable to the best results in the literature. Au decoration of 5 nm also reduced the effective turn-on field to ∼0.54 V/μm, compared to the as grown ZnO nanotapers, which showed a turn-on field of ∼1.1 V/μm. Tunneling atomic force microscopy measurements revealed a very uniform spatial emission profile in the 5 nm Au decorated nanotapers, which is a basic requirement for any large scale application. We believe that metal induced mid-gap states formed at the ZnO–Au interface are responsible for the observed low turn-on field because such interface states are known to reduce the effective work function. A direct measurement of effective work function using Kelvin probe force microscopy indeed showed more than 1.1 eV drop in the case of 5 nm Au decorated ZnO nanotapers compared to the pristine nanotapers, supporting the above argument.
Databáze: OpenAIRE
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