Photophysical properties of killer threading dislocations in Gallium Nitride epitaxial layer

Russel Sevilla^1,2*, Irwan Saleh Kurniawan^1,2, Hsiu-Ming Hsu^1,2, Hsiu-Ying Huang^1,2, Chi-Tsu Yuan^1,2

¹Department of Physics, Chung Yuan Christian University, Taoyuan, Taiwan
²Center for Semiconductor Materials and Advanced Optics, Chung Yuan Christian University, Taoyuan, Taiwan

* Presenter:Russel Sevilla, email:russelcruzsevilla@gmail.com

Threading dislocations (TDs) in gallium nitride (GaN) significantly influence its optical and electronic behavior through the introduction of deep-level states within the bandgap. Among them, threading screw and mixed dislocations can act as radiative recombination centers, though fewer than 5% exhibit detectable photoluminescence. These rare emissions originate from localized deep levels associated with specific core configurations or impurity decorations. Despite their occasional radiative activity, the deep-level states linked to killer dislocations are also known to facilitate current leakage in GaN-based power devices by promoting trap-assisted carrier transport. Spatially resolved photoluminescence analysis confirms the localized nature of radiative centers while implying a broader electrical impact from nonradiative and leakage-related states. Understanding the dual radiative and leakage roles of killer dislocations offers valuable insight into defect-mediated recombination and reliability concerns in GaN optoelectronic and power devices.

Keywords: gallium nitride, confocal microscopy, threading dislocation