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.