Roadmap for point defects in GaN

Abstract

The current status and future challenges in the field of point defects in GaN are presented. The properties of point defects, such as thermodynamic transition levels, optical energies, and charge carrier capture coefficients, are obtained from the analysis of photoluminescence, while other experimental methods are used to confirm the identification of defects. Modern first-principles calculations, their comparison with experimental results, and the main directions of their development are reviewed. Several unsolved puzzles and main challenges are outlined. Most of the discussed problems are also relevant to other semiconductors, especially direct-gap wide-bandgap semiconductors.