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226 nm AlGaN/AlN UV LEDs using p-type Si for hole injection and UV reflection

Authors :
Munho Kim
Zhenqiang Ma
Sang June Cho
Jiarui Gong
Jeongpil Park
Jung-Hun Seo
Rafael Dalmau
Weidong Zhou
Dong Liu
Baxter Moody
Deyin Zhao
Kwangeun Kim
John D. Albrecht
Akhil Raj Kumar Kalapala
Source :
Applied Physics Letters. 113:011111
Publication Year :
2018
Publisher :
AIP Publishing, 2018.

Abstract

Deep ultraviolet (UV) light-emitting diodes (LEDs) at a wavelength of 226 nm based on AlGaN/AlN multiple quantum wells using p-type Si as both the hole supplier and the reflective layer are demonstrated. In addition to the description of the hole transport mechanism that allows hole injection from p-type Si into the wide bandgap device, the details of the LED structure which take advantage of the p-type Si layer as a reflective layer to enhance light extraction efficiency (LEE) are elaborated. Fabricated LEDs were characterized both electrically and optically. Owing to the efficient hole injection and enhanced LEE using the p-type Si nanomembranes (NMs), an optical output power of 225 μW was observed at 20 mA continuous current operation (equivalent current density of 15 A/cm2) without external thermal management. The corresponding external quantum efficiency is 0.2%, higher than any UV LEDs with emission wavelength below 230 nm in the continuous current drive mode. The study demonstrates that adopting p-type Si NMs as both the hole injector and the reflective mirror can enable high-performance UV LEDs with emission wavelengths, output power levels, and efficiencies that were previously inaccessible using conventional p-i-n structures.

Details

ISSN :
10773118 and 00036951
Volume :
113
Database :
OpenAIRE
Journal :
Applied Physics Letters
Accession number :
edsair.doi...........05e5c76add0c3bdc5510411b543243b8