This course provides a comprehensive introduction to the physical and electronic properties of semiconductor materials and their applications in modern electronic and optoelectronic devices. It covers fundamental concepts such as band theory, carrier transport, recombination mechanisms, semiconductor junctions, and interfaces. The course also introduces key electronic components including bipolar and field-effect transistors, as well as advanced optoelectronic devices such as light-emitting diodes, laser diodes, and quantum cascade lasers. Emphasis is placed on understanding the physical principles governing device operation and the role of emerging semiconductor materials in advanced technologies.