| Photoreflectance (PR), a contactless form of electromodulation, is used in a study of the In1−xGa xSb alloy series. This is the first known PR report on this system. The samples consist of epilayers of In1− xGaxSb grown by molecular beam epitaxy (MBE) onto (100) GaSb substrates, resulting in percent mismatches between the substrate and layers ranging from 0.62% to 1.36%. These relatively small mismatches result in layers retaining much of their native strain well above conventional critical thickness approximations. The effects of this strain field on the optical properties are seen through shifts and splittings of the PR spectra. These are exploited to determine the relative changes in the electronic structure of the material. The compositional dependencies of the energy gaps, both at and above the fundamental absorption edge, are also presented. |
