This course explains how innovative technologies on semiconductor epitaxy produce novel devices. The understanding of semiconductor epitaxial technologies is crucial to growing the intended structures. The epitaxial technology covers Si bulk, compound-semiconductor bulk, thinfilm structures, and quantum structures. Especially, molecular-beam epitaxy and metalorganic vapor-phase epitaxy will be explained from their principles. As the application of those technologies, the course introduces the students to the laser-diode structures and their growth by different technologies.