Electronic structure of 1/6⟨20(2)over-bar3⟩ partial dislocations in wurtzite GaN

The I-1 intrinsic basal stacking faults (BSFs) are acknowledged as the principal defects observed on {11 (2) over bar0} (a-plane) and {1 (1) over bar 00} (m-plane) grown GaN. Their importance is established by recent experimental results, which correlate the partial dislocations (PDs) bounding I-1 BSFs to the luminescence characteristics of GaN. PDs are also found to play a critical role in the alleviation of misfit strain in hetero-epitaxially grown nonpolar and semipolar films. In the present study, the energetics and the electronic structure of twelve edge and mixed 1= 6 < 20 (2) over bar3 > PD configurations are investigated by first principles calculations. The specific PD cores of the dislocation loop bounding the I-1 BSF are identified for III-rich and N-rich growth conditions. The core structures of PDs induce multiple shallow and deep states, attributed to the low coordinated core atoms, indicating that the cores are electrically active. In contrast to edge type threading dislocations no strain induced states are found. (C) 2011 American Institute of Physics. [doi:10.1063/1.3569856]