Molecular beam epitaxy of GaNAs and GaInNAs

When using molecular beam epitaxy to grow GaNAs and GaInNAs with excellent crystallinity, nitrogen radicals are used as the nitrogen precursor. To suppress the generation of non-radiative centres in as-grown crystals and to eliminate them, the conditions of both growth and post-annealing have been optimized. It has been found that a relatively low growth temperature, a high growth rate and a high V/III ratio are effective for improving the crystallinity of GaInNAs. This result is possibly due to the elimination of the phase separation, because the excess atomic migration on the growing surface is suppressed under these growth conditions. It has also been found that additional rapid thermal annealing at a relatively high temperature around 750 C greatly improves the crystallinity of GaInNAs, i.e. up to the same level as conventional III-V GaInAs.