Characteristics of silent B1H mode in AlxGa1−xN alloys observed by Raman scattering

The characteristics of silent B1H mode in AlxGa1−xN alloys are studied in detail by the first-order Raman scattering. The B1H mode is observed in disordered AlxGa1−xN alloys when the polarization directions of incident and scattered lights are parallel to each other, and forbidden when they are perpendicular, which is consistent with the configuration selectivity of A1 mode indicating they have the similar vibration symmetry. In addition, origins of the observed silent B1H mode in Raman scattering and dependence of B1H mode frequency on alloy composition are discussed.