A unique set of GaP semiconductor samples studied for over 50 years has exhibited significant improvement in their properties through the formation of an impurity excitonic crystal superlattice [1-6]. In this presentation we demonstrate and discuss the importance of these crystals to application in optoelectronic devices.   These results allow new insight into solid state physics and resource-saving method for the preparation of high quality devices as well as excitonic crystal as a new advanced medium for accumulation of light and generation of non-linear optic phenomena. It is shown that their application in the electronic industry could represent a significant resource-savings and promote new generation of reliable electronic devices with interesting and useful for application properties.   On the base of this semi-centennial investigation, we propose to change existing approaches to the preparation of semiconductor materials and optoelectronic devices. This talk will discuss the promotion of these semiconductor materials on the basis of their having unique and close to ideal properties (for details please see these invited and frequently cited review articles [1-6]).