This course is concerned with semiconductor physics or in brief how semiconductor devices work. Physical aspects of semiconductors will be presented, fol­lowed by: diodes, bipolar junction transistors, and MOSFETs. Topics to be covered in the course include: Basic quantum mechanics necessary to describe how electrons behave in atoms, free space, and solid, band theory of solid: concept of conduction/valence band, concepts of electrons, holes, doping, carrier concentration, scattering, and mobility, behavior of electrons inside semiconductor when a field or concentration gradient has been present, basic operation of p-n junction (diode), operation of light emitters and detectors, bipolar junction devices, MOSFET.