Subject and UNIT: Physics for Information Science: Unit II: Semiconductor Physics
In the absence of external field, the charge carrier moves in random direction due to its thermal energy.
Subject and UNIT: Physics for Information Science: Unit II: Semiconductor Physics
The carrier concentration (ne and nh) in n-type semiconductor varies with the increase in the temperature.
Subject and UNIT: Physics for Information Science: Unit II: Semiconductor Physics
When the temperature is increased, some of the electrons in the valence band will go to acceptor energy levels by breaking up the covalent bonds and hence the Fermi level is shifted in upward direction
Subject and UNIT: Physics for Information Science: Unit II: Semiconductor Physics
For p-type at absolute zero Ep will be exactly between E and E. At low temperatures some electron from valence band fills the holes in the acceptor energy levels.
Subject and UNIT: Physics for Information Science: Unit II: Semiconductor Physics
When the temperature is increased some electrons in Ed level may be shifted to conduction band and hence some vacant sites will be created in Ed levels.
Subject and UNIT: Physics for Information Science: Unit II: Semiconductor Physics
At 0 K, EF will lie exactly between Ec and Ed, but even at low temperature some electrons may go from Ed to Ec.
types, effect, band diagram
Subject and UNIT: Physics for Information Science: Unit II: Semiconductor Physics
Impure semiconductors in which the charge carriers are produced due to impurity atoms are called extrinsic semiconductors
Intrinsic Semiconductors
Subject and UNIT: Physics for Information Science: Unit II: Semiconductor Physics
We know for intrinsic semiconductor σi = Ce -Eg/2KBT. where C is a constant.
Subject and UNIT: Physics for Information Science: Unit II: Semiconductor Physics
The electrical conductivity (σ) of an intrinsic semiconductor in terms of mobility of charge carriers.
Subject and UNIT: Physics for Information Science: Unit II: Semiconductor Physics
For an intrinsic semiconductor number of electrons (i.e,) electron density will be the same as that of number of holes (i.e.,) hole density.
Subject and UNIT: Physics for Information Science: Unit II: Semiconductor Physics
We know, at 0 K intrinsic pure semiconductor behaves as insulator. But as temperature increases some electrons move from valence band to conduction band.
Subject and UNIT: Physics for Information Science: Unit II: Semiconductor Physics
A semiconductor in a extremely pure form is called as intrinsic semiconductors.Examples: Germanium and Silicon.