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Issue 1, 2019
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13 mW operation of a 295–310 nm AlGaN UV-B LED with a p-AlGaN transparent contact layer for real world applications

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Abstract

Smart, high-power ultraviolet (UV)-B light-emitting diode (LED) light sources are demanded for both medical and agricultural applications, including vitamin D3 production in human skin (294–304 nm), immunotherapy (310 nm), cancer therapy (295–310 nm) and enriching phytochemicals in plants (310 nm). To achieve this, we have combined graded stacks of AlGaN buffer layer (BL), AlGaN multi quantum wells (MQWs) with high internal quantum efficiency (IQE), a transparent p-AlGaN contact layer, and a highly-reflective p-type electrode for the fabrication of a UV-B LED. By optimizing the growth conditions, we demonstrated an output power of 7.1 mW for a 310 nm UV-B LED under bare-wafer conditions using a highly reflective Ni/Mg p-electrode. We also demonstrated a high IQE of 47% for UV-B emission from UV-B LED at 295 nm, by using a graded n-AlGaN BL. The light-extraction efficiency (LEE) was increased by introducing both a highly-transparent p-AlGaN and a highly reflective Ni/Mg p-electrode. As a result, we achieved an EQE of 4.4% at a dc drive current of 20 mA under CW-operation at RT and a maximum output power of 13 mW for a 295 nm UV-B LED for medical applications.

Graphical abstract: 13 mW operation of a 295–310 nm AlGaN UV-B LED with a p-AlGaN transparent contact layer for real world applications

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Publication details

The article was received on 01 Aug 2018, accepted on 22 Nov 2018 and first published on 22 Nov 2018


Article type: Paper
DOI: 10.1039/C8TC03825B
J. Mater. Chem. C, 2019,7, 143-152
  • Open access: Creative Commons BY-NC license
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    13 mW operation of a 295–310 nm AlGaN UV-B LED with a p-AlGaN transparent contact layer for real world applications

    M. A. Khan, N. Maeda, M. Jo, Y. Akamatsu, R. Tanabe, Y. Yamada and H. Hirayama, J. Mater. Chem. C, 2019, 7, 143
    DOI: 10.1039/C8TC03825B

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