The influences of enhanced stacking fault (SF) formation, which is peculiar to nitrogen-(N-) polarity growth and lattice-mismatched semipolar heteroepitaxy, on the electrical properties of (10̄1̄1) Mg-doped GaN (GaN:Mg) epilayers were investigated. Although the residual donor concentration was higher than (0001) GaN because of N-polar growth, comparatively low Mg doping (3× 1019 cm-3) gave a hole concentration approximately 1.5× 1018 cm-3, which was an order of magnitude higher than (0001) GaN:Mg. As the acceptor ionization energy estimated from low temperature photoluminescence was quite similar for (10̄1̄1) and (0001) GaN:Mg, the high Mg activation seems to result with the aid of high density SFs. Because the Doppler broadening S parameter for the positron annihilation measurement, which reflects the concentration or size of negatively charged cation vacancies, of (10̄1̄1) GaN:Mg was smaller than (0001) case, (10̄1̄1) orientation is well suited to Mg-doping.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)