An Experimental Study of Dislocation Dynamics in GaN

The dynamics of dislocations introduced through indentation or scratching at room temperature into a few GaN layers that were grown using the HVPE, MOCVD and ELOG methods and had different dislocation densities were studied via the electron-beam-induced current and cathodoluminescence methods. The effects of thermal annealing and electron beam irradiation on dislocation generation and multiplication were investigated. It is shown that the Peierls barrier for dislocation glide in GaN is essentially lower than 1 eV; thus, it is mobile even at room temperature. It is shown that the mobility of a dislocation in the state-of-the-art GaN is not entirely determined by its intrinsic properties. Rather, two mechanisms may work simultaneously: overcoming the Peierls barrier and overcoming localized obstacles. The role of threading dislocations as effective obstacles for basal plane dislocation glide is demonstrated. It is shown that under low-energy electron beam irradiation, the activation energy for the dislocation glide decreases to a few tens of meV. Therefore, under e-beam irradiation, the dislocation movement is mainly controlled by overcoming localized obstacles.

Automated summary

The dynamics of dislocations introduced into GaN layers grown using different methods and with different dislocation densities were investigated. It was found that dislocation glide in GaN is possible even at room temperature with a lower than 1 eV Peierls barrier. The mobility of dislocations in GaN is determined by both overcoming the Peierls barrier and localized obstacles. Thread dislocations were found to be effective obstacles for basal plane dislocation glide. Under low-energy electron beam irradiation, the activation energy for dislocation glide decreases, indicating that localized obstacles become the main controlling factor.