Physics Form 5: Chapter 4 - Semiconductor

Semiconductor is a material where its electrical conductivity lie between conductors and insulators. In semiconductors, thermal energy is enough to cause a small number of electrons to escape from the valence band of atom to the higher energy of conduction band, in which they are relatively free to move. The resulting gaps in the valence band are called holes.

Usually, semiconductors are made from semi-metal or called metalloid from the Periodic Table. 

Silicon is the most preferred material for semiconductors because:

• ease of availability
• low cost of processing 
• higher temperature range
• high resistivity than other counterparts 
• low leakage current

Semiconductors are widely use in making diode, transistor and integrated circuit