Bonding of nitrogen in dilute GaInAsN and AlGaAsN studied by Raman spectroscopy

To gain information on the local bonding of the nitrogen, Ga1−xInxAs1−yNy with x⩽0.12 and y⩽0.04 and AlxGa1−xAs1−yNy with x⩽0.05 and y⩽0.04 have been studied by Raman spectroscopy. When adding In to GaAsN, the nitrogen-induced vibrational mode near 470 cm−1 observed in GaAsN was found to split into up to three components, with one of the In–N related modes at higher and the other at lower frequencies than the Ga–N mode. Upon thermal annealing, the relative mode intensities were found to change in favor of the In–N related modes, indicating a redistribution of the III–N bonds. For AlxGa1−xAs0.99N0.01, in contrast, the almost exclusive formation of complexes with Al-to-N bonding was observed already for a low Al content of x=0.05, as seen from a complete switch in mode intensity from the Ga–N mode at 470 cm−1 to a new Al–N related mode near 450 cm−1. This result was confirmed by a corresponding analysis of the quinary compound AlGaInAsN.