Dopant

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A dopant, also called doping agent and dope, is an impurity element added to a semiconductor lattice in low concentrations in order to alter the optical/electrical properties of the semiconductor.

The process of introducing dopants into a semiconductor is called doping.

The addition of a dopant to a semiconductor has the effect of shifting the Fermi level within the material. This results in a material with predominantly negative (n type) or positive (p type) charge carriers depending on the dopant species. Pure semiconductors altered by the presence of dopants are known as extrinsic semiconductors (cf. intrinsic semiconductor). Dopants are introduced into semiconductors in a variety of techniques: solid sourcs, gases, spin on liquid and ion implanting. See ion implantation, surface diffusion, and solid sources footnote.

[edit] Examples

footnote: for further information see http://www.techneglas.com/dopantpages/boroncatalog.htm

Boron, arsenic, phosphorus, antimony, among other substances, are commonly used dopants in the semiconductor industry.

The medical field has some use for Erbium in as a dopant for lasers used in surgery. Europium is used to dope plastics in lasers. Holmium is used as to dope Yttrium-Aluminium Garnets used in laser surgery. (Source: Strategic Rare Earth Metals Inc.)