Spatially resolved photoluminescence of inversion domain boundaries in GaN-based lateral polarity heterostructures

Intentionally grown GaN inversion domain boundaries (IDBs) of lateral polar ity heterostructures have been spectroscopically imaged at low temperature using high spatial resolution photoluminescence. It is shown that the IDBs are not only optically active, but are more than an order of magnitude brig hter than the GaN bulk material. Our findings are in agreement with calcula tions predicting that IDBs should not adversely affect near-band-gap photol uminescence due to the absence of midgap electronic states. Typical linewid ths are on the order of 10-20 meV, however, features less than 0.6 meV are observed. The boundary emission is found to be neither spectrally nor spati ally uniform. Also, a strong polarization dependence of the IDB photolumine scence is measured and determined to be oriented parallel to the boundary b etween GaN of N- or Ga-face polarity. (C) 2001 American Institute of Physic s.