Semiconductor diode

Posted by AJ On Tuesday, 9 July 2013 0 comments

Fig – a semiconductor diode symbol

Basic operation

Fig – b Vi characteristics of a diode

n-type versus p-type

• n-type materials make the Silicon (or Germanium) atoms more negative.

• p-type materials make the Silicon (or Germanium) atoms more positive.

• Join n-type and p-type doped Silicon (or Germanium) to form a p-n junction.

p-n junction

• When the materials are joined, the negatively charged atoms of the n-type doped side

are attracted to the positively charged atoms of the p-type doped side.

• The electrons in the n-type material migrate across the junction to the p-type material

(electron flow).

• the ‘holes’ in the p-type material migrate across the junction to the n-type material

(conventional current flow).

• The result is the formation of a depletion layer around the junction.

Depletion region

aj set