Heteroepitaxy is a process used in materials science to grow a thin layer of one material on top of a different substrate material. This technique is essential for creating semiconductor devices, where layers of different materials are needed to achieve specific electronic properties. The quality of the interface between the two materials is crucial for the performance of the final product. In heteroepitaxy, the lattice structures of the two materials must be compatible to minimize defects. This compatibility allows for better electronic and optical properties, making it vital in the development of advanced technologies like solar cells and LEDs.