Application of multiphoton photoluminescence in characterization of GaN dislocations

As one of the third-generation semiconductors, gallium nitride (GaN) materials have become a hot spot of research at home and abroad due to its unique properties and application prospects, and the preparation of high-quality GaN single-crystal substrates is the basis for obtaining optoelectronic devices and power devices with excellent performance. However, the high dislocation density of GaN seriously affects the stability and reliability of GaN devices, limiting their further development. Therefore, a new technique is needed to further explore the formation, generation and merging of dislocations. In this paper, we review a new testing method for 3D imaging dislocations, and briefly introduce the origin of threading dislocations and working principle of multiphoton photoluminescence (MPPL). The applications of MPPL in threading dislocations was discussed in detail. Finally, the challenges and opportunities faced by MPPL in characterizing GaN dislocations were described, and its future prospects were discussed.