Tunnel-injected sub 290 nm ultra-violet light emitting diodes with 2.8% external quantum efficiency
Abstract
We report on the high efficiency tunnel-injected ultraviolet light emitting diodes (UV LEDs) emitting at 287 nm. Deep UV LED performance has been limited by the severe internal light absorption in the p-type contact layers and low electrical injection efficiency due to poor p-type conduction. In this work, a polarization engineered Al0.65Ga0.35N/In0.2Ga0.8N tunnel junction layer is adopted for non-equilibrium hole injection to replace the conventionally used direct p-type contact. A reverse-graded AlGaN contact layer is further introduced to realize a low resistance contact to the top n-AlGaN layer. This led to the demonstration of a low tunnel junction resistance of 1.9 × 10−3 Ω cm2 obtained at 1 kA/cm2. Light emission at 287 nm with an on-wafer peak external quantum efficiency of 2.8% and a wall-plug efficiency of 1.1% was achieved. The measured power density at 1 kA/cm2 was 54.4 W/cm2, confirming the efficient hole injection through interband tunneling. With the benefits of the minimized internal absorption and efficient hole injection, a tunnel-injected UV LED structure could enable future high efficiency UV emitters.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Feb 12, 2018
- Source ID
- 10.1063/1.5017045
Entities
People
- Andrew A. Allerman
- Andrew Armstrong
- Fatih Akyol
- Gabriel Calderon
- Jared Johnson
- Jinwoo Hwang
- Michael W. Moseley
- Sanyam Bajaj
- Siddharth Rajan
- Yuewei Zhang
- Zane Jamal-eddine
Organizations
- Air Force Office of Scientific Research
- National Science Foundation
- Office of Naval Research
- Ohio State University
- Sandia National Laboratories