Correlation between Dislocation Density and the Macroscopic Properties of GaN Grown by Metalorganic Vapor Phase Epitaxy

The correlation between the dislocation density and the electrical and optical properties of lightly Si-doped GaN films grown by metalorganic vapor phase epitaxy was investigated. Photo-electro-chemical (PEC) etching, developed by Youtsey et al.. [Appl. Phys. Lett. 73 (1998) 797], was applied to determine the dislocation density. We modified the PEC etching technique by introducing an additional pulsed sequence. Clear correlation was observed between the dislocation density and the Hall mobility and room-temperature photoluminescence intensity. The influence of the reactor pressure on the dislocation density is also discussed.