Test: Electrons & Holes in Semiconductor - Electrical Engineering (EE) MCQ

The distribution of the electrons in the conduction band is given by the product of the density into Fermi-dirac distribution.

Substituting the values of m_n=m0 ,h=6.626*10^-34J/s ,k=1.38*10^-23 and T=300K, we get
Nc=2.5*10¹⁹ cm^-3.

In a semiconductor, two types of charges are there by which the flow of the current takes place. So, both the holes and electrons take part in the flow of the current.

It is the correct formula for the Fermi probability function.

 As the temperature rises above 0 k, the electrons gain energy and rises to the conduction band from the valence band.

 Using the formula,

We get, ni=1.5*10¹⁰cm^-3.

From the above formula, E_fidepends on all of the options given.

This is practically proved.

The electrons and holes depends upon the effective density of the states and the Fermi energy level given by the formula,

 In the intrinsic semiconductor, ni=pi that is the number of the electrons is equal to the number of the holes. Whereas in the extrinsic conductor ni is not equal to pi.