This project is built on the concept of a novel type of quantum dots: crystal-phase quantum dots (CPQDs), which consist of heterostructures made with a single material but having different crystal phases. Compared to conventional quantum dots, formed using different materials, CPQDs have a unique advantage: they can be grown with the ultimate accuracy of a single atomic layer. Even though CPQDs have several superior characteristics with respect to conventional quantum-dots, their technological application has been severely limited by the poor understanding of the phase switching mechanism and the difficulty of controlling their formation. In this project, we will break this limitation by using an electric field to trigger the phase change in GaAs nanowires and in doing so, to create CPQDs with the ultimate monolayer precision. This will represent a breakthrough in the fabrication of CPQDs and will unlock their potential for several applications in quantum optics.