Semiconducter
What is conductor?
Conductors are materials that permit
electrons to flow freely from particle to
particle.
Ex : iron,coper,silver etc.
Intrinsive semiconder
natural/pure/without any impurity
Intrinsic semiconductors are those made from the purest
form of semiconductor material.
1. silicon(z=14)
Valency =4
2. germanium(z=32)
Valency =4
#Both have 4 valence electrons.
#All 4 valence electron are involved in covalent bond in
formation in silicon and germanium.
Eg=1.1ev Si
Eg=0.72ev Ge
pure
1. at absolute temp. 0 kelvin there are no free electrons .
2. as all the valence electron are involved in covalent bond .
semiconductor will
behave like an
insulator at 0
kelvin
Providing external energy in the form of heat (300k)
e
Hole: vacancy due to thermally generated free electron
holes are positively charged
- => e-+
.