Optical characterization of InGaAsP/InP(001) heterostructures

Reflectance anisotropy spectroscopy was applied for investigation of the In$_{0.8}$Ga$_{0.2}$As$_{0.5}$P$_{0.5}$ solid solution films. Films with a thickness of 50–1000 nm were grown on InP(001) substrates using a buffer layer of different thicknesses. It was found that during storage, samples with a buffer layer 1 $\mu$m thick can degrade. Degradation probably occurs in the region of the buffer layer and is accompanied by relaxation of internal stress in the structure. At the same time, the intensity of photoluminescence decreases, while the film surface relief does not change.