229 nm UV LEDs on aluminum nitride single crystal substrates using p-type silicon for increased hole injection
Abstract
AlGaN based 229 nm light emitting diodes (LEDs), employing p-type Si to significantly increase hole injection, were fabricated on single crystal bulk aluminum nitride (AlN) substrates. Nitride heterostructures were epitaxially deposited by organometallic vapor phase epitaxy and inherit the low dislocation density of the native substrate. Following epitaxy, a p-Si layer is bonded to the heterostructure. LEDs were characterized both electrically and optically. Owing to the low defect density films, large concentration of holes from p-Si, and efficient hole injection, no efficiency droop was observed up to a current density of 76 A/cm2 under continuous wave operation and without external thermal management. An optical output power of 160 μW was obtained with the corresponding external quantum efficiency of 0.03%. This study demonstrates that by adopting p-type Si nanomembrane contacts as a hole injector, practical levels of hole injection can be realized in UV light-emitting diodes with very high Al composition AlGaN quantum wells, enabling emission wavelengths and power levels that were previously inaccessible using traditional p-i-n structures with poor hole injection efficiency.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Feb 19, 2018
- Source ID
- 10.1063/1.5011180
Entities
People
- Baxter Moody
- Deyin Zhao
- Dong Liu
- In-Kyu Lee
- Jeongpil Park
- Jiarui Gong
- John D. Albrecht
- Jung-Hun Seo
- Kwangeun Kim
- Munho Kim
- Rafael Dalmau
- Sang June Cho
- Weidong Zhou
- Zhenqiang Ma
Organizations
- Michigan State University
- University of Texas at Arlington
- University of Wisconsin–Madison