Correlation of growth behavior and spectral properties of GaN grown by the Na-flux method

With the demand for optoelectronic applications, homoepitaxial gallium nitride (GaN) exhibits remarkable advantages owing to its extremely low dislocation density and other superior properties. The Na-flux method represents a promising approach for growing high‑quality GaN single crystals. However, the correlation between the growth behavior and spectral properties of the Na-flux GaN remains elusive. In this work, self‑assembled GaN microdisks were synthesized via the Na-flux method. Cathodoluminescence (CL) spectroscopy revealed distinct optical differences between regions with different growth behaviors, in which defect‑related luminescence was dominant. Spatially resolved Raman spectroscopy was employed to systematically investigate the stress, crystalline quality, and defects associated with different growth behaviors. Combined with complementary characterization techniques, it is suggested that the lateral-growth regions contain a higher concentration of V Ga -related defect complexes accompanied by oxygen incorporation. This study furthers our understanding of the optical behavior and spectral variations among different growth behaviors of the Na-flux GaN, facilitating the application of GaN‑based optoelectronic devices.