Semiconductor superlattices are structures made by stacking alternating layers of different semiconductor materials, typically just a few nanometers thick. This layering creates unique electronic properties that differ from those of the individual materials. The arrangement allows for control over the energy levels of electrons, which can enhance the performance of electronic devices. These superlattices are crucial in developing advanced technologies, such as quantum wells and laser diodes. By manipulating the thickness and composition of the layers, researchers can tailor the materials for specific applications, improving efficiency in devices like solar cells and transistors.