Semiconductor

2 definitions found

From WordNet (r) 2.0 [wn]:

  semiconductor
       n 1: a substance as germanium or silicon whose electrical
            conductivity is intermediate between that of a metal and
            an insulator; its conductivity increases with
            temperature and in the presence of impurities [syn: {semiconducting
            material}]


       2: a conductor made with semiconducting material [syn: {semiconductor
          device}, {semiconductor unit}]

From The Free On-line Dictionary of Computing (27 SEP 03) [foldoc]:

  semiconductor
       
           A material, typically crystaline, which allows
          {current} to flow under certain circumstances.  Common
          semiconductors are silicon, germanium, gallium arsenide.
          Semiconductors are used to make {diodes}, {transistors} and
          other basic "solid state" electronic components.
       
          As crystals of these materials are grown, they are "doped"
          with traces of other elements called {donors} or {acceptors}
          to make regions which are n- or p-type respectively for the
          {electron model} or p- or n-type under the {hole model}.
          Where n and p type regions adjoin, a junction is formed which
          will pass {current} in one direction (from p to n) but not the
          other, giving a {diode}.
       
          One {model} of semiconductor behaviour describes the doping
          elements as having either {free electrons} or {holes} dangling
          at the points in the crystal lattice where the doping elements
          replace one of the atoms of the foundation material.  When
          external electrons are applied to n-type material (which
          already has free electrons present) the repulsive force of
          like charges causes the free electrons to migrate toward the
          junction, where they are attracted to the holes in the p-type
          material.  Thus the junction conducts current.
       
          In contrast, when external electrons are applied to p-type
          material, the attraction of unlike charges causes the holes to
          migrate away from the junction and toward the source of
          external electrons.  The junction thus becomes "depleted" of
          its charge carriers and is non-conducting.
       
          (1995-10-04)