Photoreflectance of InSb/GaAs heterostructures at E1 and E1+Δ1 transitions

The photoreflectance spectra of InSb/GaAs heterostructures at the E₁ and E₁+Δ₁ transitions have been measured as a function of layer thickness. The spectra show an increase in lineshape broadening, similar to that observed in the increase in FWHM of the X-ray diffraction peaks, as the film thickness decreases. The data indicate increased crystal quality with increasing layer thickness. The results show that photoreflectance can be used as a tool to study the structural quality of lattice-mismatched heterostructures