Influence of intrinsic or extrinsic doping on charge state of carbon and its interaction with hydrogen in GaN

It has been established that the formation of point defects and their behaviors could be regulated by growth details such as growth techniques and growth conditions. In this work, we prove that C doping approaches have great influence on the charge state of C N, thus the interaction between H and C in GaN. For GaN with intrinsic C doping, which is realized by reducing the V/III ratio, C N mainly exists in the form of C N − charged from the higher concentration of V N and, thus, may attract H + by coulomb interaction. Whereas for the extrinsically C doped GaN with propane as the doping source, the concentration of V N is reduced, and C N mainly exists in neutral charge state and, thus, nearly does not attract H ions. Therefore, we demonstrate that the interplay between H and C atoms is weaker for the extrinsically C doped GaN compared to the intrinsically doped GaN, thus gives a clear picture about the different charge states of C N and the formation of C–H complexes in GaN with different C doping approaches.