Surface Brillouin scattering from acoustic phonons. II. Application to semiconductors

The theory of Brillouin scattering from corrugated surfaces developed previously has been applied to semiconductors. The available spectra measured with 5145 AA light has been used for evaluating the elasto-optic constants (k₁₁, k₁₂, k₄₄) of the medium. For GaAs k₁₁=42.5, k₁₂=51 and k₄₄=25.5. This is the first determination of these constants in GaAs at this wavelength, where other techniques are not applicable. For silicon k₁₁=53, k₁₂=25 and k₄₄=23. It is also shown that in opaque semiconductors the elasto-optic coupling depends strongly on the surface orientation.