Semiconductors are the materials which have a conductivity between conductors known as metals and non-conductors or insulators such ceramics. Semiconductors can be compounds such as gallium arsenide or pure elements, such as germanium or silicon. Semiconductors can be classified as intrinsic semiconductors and extrinsic semiconductors. The difference between the two is explained below.
|Intrinsic Semiconductor||Extrinsic Semiconductor|
|Pure type of semiconductor||Impure type of semiconductor|
|Density of electrons is equal to the density of holes||Density of electrons is not equal to the density of holes|
|Electrical conductivity is low||Electrical conductivity is high|
|Dependence on temperature only||Dependence on temperature as well as on the amount of impurity|
|The bandgap between conduction (C.B) and valence band (V.B) is small.||The energy gap is higher than the intrinsic semiconductors.|
|Examples: Si, Ge||Examples: GaAs, GaP|