Polarized Raman spectra and N-related local vibrational mode in GaNAs and GaInNAs epitaxial layers grown on GaAs

Raman studies were performed on GaN(0.025)As(0.975) and Ga(0.94)In(0.06)N(0.025)As(0.975) epilayers grown on (100) GaAs. N alloying enhanced the forbidden TO phonon, while In alloying had a negligible effect on it. The forbidden TO phonon had an A(1) symmetry, in contrast to that of Ga(0.969)In(0.031)As having a T(2) symmetry. In GaInNAs, thermal annealing led to the splitting of a N-related local vibrational mode (LVM) into a doublet (472 and 490 cm(-1)), while no change was observed in GaNAs. LVM is discussed in terms of In-N bond formation.