03-10-2012, 05:43 PM
ME-2255 Electronics and Microprocessor
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Metal or conductor:
–It having overlapping Valance and conduction band
–Free electron is 10 28e-1/m3
•Semiconductor:
–No. of free e-1is lies b/w 107e-1/m3 to 10 28e-1/m3
–S.C conductivity greater than insulator but less than conductor.
–E.g. Silicon (Si), Germanium (Ge)
Types of semiconductor:
•Intrinsic semiconductor
–Pure Si or Ge semiconductor is known as intrinsic s.c
–Due to shortage of free electron and holes, Conductivity of pure s.c is very poor
•Extrinsic semiconductor
–To increase the conductivity, impurities are added to pure s.c. after adding impurity s.c is extrinsic s.c
P-type Semiconductor:
–A small amount of trivalent impurities such as aluminium or boron is added to the pure semiconductor to get the p-type semiconductor.
[attachment=35203]
Metal or conductor:
–It having overlapping Valance and conduction band
–Free electron is 10 28e-1/m3
•Semiconductor:
–No. of free e-1is lies b/w 107e-1/m3 to 10 28e-1/m3
–S.C conductivity greater than insulator but less than conductor.
–E.g. Silicon (Si), Germanium (Ge)
Types of semiconductor:
•Intrinsic semiconductor
–Pure Si or Ge semiconductor is known as intrinsic s.c
–Due to shortage of free electron and holes, Conductivity of pure s.c is very poor
•Extrinsic semiconductor
–To increase the conductivity, impurities are added to pure s.c. after adding impurity s.c is extrinsic s.c
P-type Semiconductor:
–A small amount of trivalent impurities such as aluminium or boron is added to the pure semiconductor to get the p-type semiconductor.