Three-dimensional photoluminescence imaging of threading dislocations in GaN by sub-band optical excitation

Abstract GaN is rapidly gaining attention for implementation in power electronics but is still impacted by its high density of threading dislocations (TDs), which have been shown to facilitate current leakage through devices limiting their performance and reliability. Here, we discuss a novel implem...

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Main Authors: Matthias Daeumer, Jae-Hyuck Yoo, Zhiyu Xu, Minkyu Cho, Marzieh Bakhtiary-Noodeh, Theeradetch Detchprohm, Yuxuan Zhang, Vijay Gopal Thirupakuzi Vangipuram, Vishank Talesara, Yibo Xu, Edward Letts, Daryl Key, Tian T. Li, Qinghui Shao, Russell Dupuis, Shyh-Chiang Shen, Wu Lu, Hongping Zhao, Tadao Hashimoto, Ted A. Laurence
Format: Article
Language:English
Published: Nature Portfolio 2025-01-01
Series:Scientific Reports
Online Access:https://doi.org/10.1038/s41598-024-83398-0
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Summary:Abstract GaN is rapidly gaining attention for implementation in power electronics but is still impacted by its high density of threading dislocations (TDs), which have been shown to facilitate current leakage through devices limiting their performance and reliability. Here, we discuss a novel implementation of photoluminescence (PL) imaging to study TDs in regions within vertically structured p-i-n GaN (PIN) diodes consisting of metalorganic chemical vapor deposition (MOCVD) epitaxial layers grown on ammonothermal GaN (am-GaN) substrates. PL imaging with a sub-bandgap excitation energy (3.1 eV) reveals TDs with excellent clarity in three dimensions within the am-GaN substrate. Galvanometric-driven PL imaging allows the microstructure of hundreds of devices to be characterized in a single session, enhancing the screening process through the addition of device specific TD location tracking and density mapping. The visibility, structural characteristics, luminescent nature and evolution of TDs through the GaN growth process are described, potentially providing the ability to define TD structures associated with leakage current.
ISSN:2045-2322