Semiconductor nanostructures are referred to semiconductor heterostructures confined in one, two, or all three dimensions, which are known as quantum wells, quantum wires, and quantum dots (QDs), respectively. QDs are semiconductor nanocrystals with significant potential for high-performance photonic and electronic devices based on III–V semiconductor alloys. To fabricate these structures, several methods have been developed, including chemical synthesis of colloidal QDs, Stranski–Krastanov (S–K) growth technology, and droplet epitaxy (DE). DE is an epitaxial technique primarily employed for fabrication of nanostructures based on III–V semiconductors for quantum information technology applications. This work presents a DE technology of growth of InGaP nanocrystals on GaP surface. The technology includes the electrochemical deposition of group III metals on the III–V semiconductor surface, followed by annealing in inert gas atmosphere. The photoelectric and photonic properties of the resulting nanomaterials are analyzed. Based on the experimental results and literature data, the growth mechanism of InGaP nanocrystals on the GaP surface is described, and a phenomenological model for the formation of InGaP/GaP nanostructures is proposed.