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Introduction to Electronics and Semiconductors

What is a Semiconductor?A semiconductor is a material that has electrical conductivity between that of a conductor (such as copper) and an insulator (such as glass). Its resistance decreases as the temperature rises, which is the opposite behavior of metals.Intrinsic vs. Extrinsic SemiconductorsAn intrinsic semiconductor is a pure semiconductor without any significant dopant species present. Silicon and Germanium are common examples. An extrinsic semiconductor has been doped with impurities to change its electrical properties.N-Type and P-Type DopingDoping introduces small amounts of foreign atoms. In N-type doping, pentavalent impurities (like Phosphorus) are added, creating extra free electrons. In P-type doping, trivalent impurities (like Boron) are added, creating holes (absence of electrons).