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Q. 17

Why are elemental dopants for Silicon or Germanium usually chosen from group XIII or group XV?

Class 12th Physics - Exemplar 14. Semiconductor Electronics

Answer :

When a pure semiconductor is mixed with a small amount of impurities i.e. elements having number of valence electrons slightly different, the concentration of charge carries changes dramatically. So to increase the number of a particular type of charge carriers the Silicon and Germanium crystals that are elements of group XIV, are doped with a small amount of the elements of groups XIII or XV.

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PREVIOUSThe breakdown in a reverse biased p–n junction diode is more likely to occur due to NEXTSn, C, and Si, Ge are all group XIV elements. Yet, Sn is a conductor, C is an insulator while Si and Ge are semiconductors. Why?

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