Doping (semiconductors)

Doping is the deliberate introduction of impurity atoms into a semiconductor to control its electrical conductivity and carrier type. Donor dopants supply electrons; acceptor dopants create holes.

Donor: An impurity or defect that supplies an electron to a semiconductor’s conduction band. Donor dopants produce the excess electrons that make a semiconductor n-type.
Semiconductor: A material whose electrical conductivity lies between that of a conductor and an insulator and can be controlled. Doping modifies the carrier population in this broader class of materials.
p–n junction: A boundary between p-type and n-type semiconductor regions that forms a rectifying electrical interface. Joining differently doped regions creates the built-in field central to many devices.
Intrinsic semiconductor: A semiconductor without intentional dopants, whose carriers arise from thermal excitation or other intrinsic processes. It contrasts with extrinsic material whose carrier population is deliberately altered by impurities.
Acceptor: An impurity or defect that accepts an electron, leaving a mobile hole in a semiconductor’s valence band. Acceptor dopants create the holes that make a semiconductor p-type.
Energy band: A range of allowed electron energies in a solid, formed by the collective states of its atoms. Dopant states are understood relative to a semiconductor’s valence and conduction bands.
Transistor: A semiconductor device that controls current or voltage and can amplify or switch electrical signals. Spatially controlled doping establishes the regions that let transistors switch and amplify.
n-type semiconductor: An extrinsic semiconductor in which electrons are the majority mobile carriers. Donor doping produces this carrier type.
Fermi level: The electron chemical potential in a solid, which determines how electronic states are occupied. Doping shifts the Fermi level toward the conduction or valence band.
Crystal lattice: The repeating geometric arrangement of atoms in a crystalline solid. Substitutional dopants occupy lattice sites and inherit their local bonding environment.

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