Raman Scattering form Periodic and Nonperiodic GaSb/AlSb Strained-Layer Lattices

Lattice dynamics measurements have been performed on a series of periodic and nonperiodic strained-layer GaSb/AlSb lattices using Raman scattering. In the optical frequency region for periodic lattices quantum confined longitudinal optic phonons have been observed in GaSb layers with widths less than 25 angstroms. Spatially extended interface modes lying within the LO-TO regions for both GaSb and AlSb have also been observed. The interface mode frequencies we have observed are not particularly well fit by current macroscopic theories. We have found that both the peak frequencies and relative intensities of our finite length Fibonacci lattices are reasonably modeled by the latter periodic lattice.