In `mu_e` and `mu_h` are electron and hole mobility. E be the applied electric field, the current density `tau` for intristic semiconductor is equal to

The electric field E, current density j and conductivity sigma of a conductor are related as

Electric field (E) and current density (J) have relation

The expression for Ohm's law in terms of electric field E and current density J is:-

The electric intesity E, current density j and conductivity sigma are related as:

Let n_(e) and n_(b) are the number density of electrons and holes in extrinsic semiconductor then-

Using the microscopic form of Ohm's law (J=sigma E) , prove that conductivity of a metal can be written as sigma="ne"mu . Here n is the number of free electrons per unit volume and mu is mobility of free electrons . In case of semiconductors there are two types of conduction particles, one is free electrons and the other is known as a hole. Charge on the hole may be assumed to be equal and opposite of that on electron. The number density of free electrons and holes in the semiconducting material are n and p respectively. Assuming mu_e and mu_h as mobility of free electrons and holes respectively , write the exopression of conductivity of the semiconducting material.

Lets n_p and n_e be the number of holes and conduction electrons in an intrinsic semiconductor.

The electrical energy density (mu) stored in an electric filed intensity E is