In a pure Semi conductor number of electrons = number of holes. Thermal agitation (increase in temperature) produces new electron-hole pairs and these electron-hole pair combines produces new charge particles.
one particle is of negative charge which is known as free electron with mobility another in with positive charge known as free hole with mobility .
two particles moves in opposite direction in an electric field and constitutes a current.
The total current density (J) with in the semi conductor.
Total conduction current density = conduction current density due to electrons + conduction current density due to holes.
n- number of electrons/Unit-Volume.
p-number of holes/Unit-Volume.
E- applied Electric field strength V/m.
q-charge of electron/hole
where is the conductivity of semi conductor.
Intrinsic Semi conductor:-
In an intrinsic semi conductor
where is the current density in an intrinsic semi conductor
Conductivity in N-type semi conductor:-
number of electrons number of holes
Conductivity in P-type semi conductor:-
number of holes number of electrons