The influence of the interaction mechanism between impurities and point defects on the yellow luminescence band of GaN

The yellow luminescence (YL) band is commonly observed in gallium nitride (GaN) crystals grown through various methods, and its presence can have detrimental effects on the electronic and optical properties of devices, leading to device degradation. However, the intensity of YL emission exhibits significant variations among different samples. Therefore, it is crucial to investigate the causes of YL generation and these differences in order to mitigate YL formation. In this paper, we present an analysis of four GaN samples grown by hydride vapor phase epitaxy (HVPE) and Ammonothermal method using photoluminescence (PL) spectroscopy and demonstrate that carbon plays a significant role in enhancing YL emission. Additionally, we explore the differential impact of various YL bands on total emission (YL1>YL3>YL2, they correspond to the YL emissions at 2.17 eV, 2.3 eV, and 2.07eV, respectively.). By comparing the relative content levels of different non-radiative point defects, we propose that impurity content variation (particularly elemental carbon) greatly influences YL emission behavior. This provides a novel perspective for understanding the mechanism behind YL formation.