Typical photoreflectance lineshapes related to simple and complex wafer structures are reviewed and the transient behavior of photoreflectance spectrum components is analyzed in detail. The amplitude and phase delay of different PR spectrum features as function of modulation frequency are derived. A fitting procedure for the photoreflectance spectrum with special consideration of the Seraphin coefficients is developed to extract the physical parameters for materials and devices. It applies very well to photoreflectance experiments carried out on GaAs wafer materials, and VCSEL devices. (C) 2003 Elsevier B.V. All rights reserved.