Hybrid tunnel junction contacts to III-nitride light-emitting diodes

• Published in: Applied physics express Vol. 9; no. 2; pp. 22102 - 22105
• Main Authors: Young, Erin C., Yonkee, Benjamin P., Wu, Feng, Oh, Sang Ho, DenBaars, Steven P., Nakamura, Shuji, Speck, James S.
• Format: Journal Article
• Language: English
• Published: The Japan Society of Applied Physics 01.02.2016
• ISSN: 1882-0778; 1882-0786
• DOI: 10.7567/APEX.9.022102

In this work, we demonstrate highly doped GaN p-n tunnel junction (TJ) contacts on III-nitride heterostructures where the active region of the device and the top p-GaN layers were grown by metal organic chemical vapor deposition and highly doped n-GaN was grown by NH3 molecular beam epitaxy to form the TJ. The regrowth interface in these hybrid devices was found to have a high concentration of oxygen, which likely enhanced tunneling through the diode. For optimized regrowth, the best tunnel junction device had a total differential resistivity of 1.5 × 10−4 Ω cm2, including contact resistance. As a demonstration, a blue-light-emitting diode on a () GaN substrate with a hybrid tunnel junction and an n-GaN current spreading layer was fabricated and compared with a reference sample with a transparent conducting oxide (TCO) layer. The tunnel junction LED showed a lower forward operating voltage and a higher efficiency at a low current density than the TCO LED.