Issue 4, 2020

A broadband ultraviolet light source using GaN quantum dots formed on hexagonal truncated pyramid structures

Abstract

Group III-nitride semiconductor-based ultraviolet (UV) light emitting diodes have been suggested as a substitute for conventional arc-lamps such as mercury, xenon and deuterium arc-lamps, since they are compact, efficient and have a long lifetime. However, in previously reported studies, group III-nitride UV light emitting diodes did not show a broad UV spectrum range as conventional arc-lamps, which restricts their application in fields such as medical therapy and UV spectrophotometry. Here, we propose GaN quantum dots (QDs) grown on different facets of hexagonal truncated pyramid structures formed on a conventional (0001) sapphire substrate. A hexagonal truncated GaN pyramid structure includes {10[1 with combining macron]1} semipolar facets as well as a (0001) polar facet, which have intrinsically different piezoelectric fields and growth rates of GaN QDs. Consequently, we successfully demonstrated a plateau-like broadband UV spectrum ranging from ∼400 nm (UV-A) to ∼270 nm (UV-C) from the GaN QDs. In addition, at the top-edge of the truncated pyramid structure, a strain was locally suppressed compared to the center of the truncated pyramid structure. As a result, various emission wavelengths in the UV range were achieved from the GaN QDs grown on the sidewall, top-edge and top-center of hexagonal truncated pyramid structures, which ultimately provide a broadband UV spectrum with high efficiency.

Graphical abstract: A broadband ultraviolet light source using GaN quantum dots formed on hexagonal truncated pyramid structures

Supplementary files

Article information

Article type
Paper
Submitted
02 Dec. 2019
Accepted
10 Febr. 2020
First published
11 Febr. 2020
This article is Open Access
Creative Commons BY-NC license

Nanoscale Adv., 2020,2, 1449-1455

A broadband ultraviolet light source using GaN quantum dots formed on hexagonal truncated pyramid structures

J. Cho, S. Lim, M. Jang, C. Lee, H. Yeo, Y. C. Sim, J. Kim, S. Matta, B. Alloing, M. Leroux, S. Park, J. Brault and Y. Cho, Nanoscale Adv., 2020, 2, 1449 DOI: 10.1039/D0NA00052C

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