Experimental set-up has been established by using high resolution monochromator as well as He-Ne and Ar multiline lasers. Epitaxial, undoped and doped (Si and Zn) GaAs and GaAlAs layers as well as heterostructures of GaAs/GaAlAs have been grown in atmospheric pressure vertical MOCVD system. Room temperature photoreflectance (PR) have been applied to characterize layers, heterostructures as well as the multiple quantum wells. The surface and interface related PR have been studied by means of Kramers-Kronig analysis. Decomposition of PR spectrum into the spectra connected with surface region and with the interface has been proposed. Modulus of the complex photoreflectance gives us the critical point energy, whereas the phase of this function can be used for a carrier concentration topography.