Near band edge photoluminescence of ZnO nanowires: Optimization via surface engineering

Zinc oxide (ZnO) nanowire arrays have potential applications for various devices such as ultra-violet light emitting diodes and lasers, where photoluminescence of intense near band edge emission without defect emissions is usually desired. Here, we demonstrate, counter-intuitively, that the near ban...

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Bibliographic Details
Published in:Applied physics letters 2017-12, Vol.111 (23)
Main Authors: Yan, Danhua, Zhang, Wenrui, Cen, Jiajie, Stavitski, Eli, Sadowski, Jerzy T., Vescovo, Elio, Walter, Andrew, Attenkofer, Klaus, Stacchiola, Darío J., Liu, Mingzhao
Format: Article
Language:English
Subjects:
Applied physics
Emission
Light emitting diodes
Low pressure
MATERIALS SCIENCE
Minority carriers
Nanowires
Organic light emitting diodes
Photoluminescence
Screens
Surface defects
Valence band
Zinc oxide
Zinc oxides
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Summary:Zinc oxide (ZnO) nanowire arrays have potential applications for various devices such as ultra-violet light emitting diodes and lasers, where photoluminescence of intense near band edge emission without defect emissions is usually desired. Here, we demonstrate, counter-intuitively, that the near band edge emission may become dominant by introducing certain surface defects to ZnO nanowires via surface engineering. Specifically, near band edge emission (NBE) is effectively enhanced after a low pressure O2 plasma treatment that sputters off surface oxygen species to produce a reduced and oxygen vacancy-rich surface. The effect is attributed to the lowered surface valence band maximum of the reduced ZnO surface that creates an accumulative band bending, which screens the photo-generated minority carriers (holes) from reaching or being trapped by the surface defects.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.5001043