Question

What is fermi level? Mention its position in n-type & p-type semiconductors

Answer 1

Answer: Fermi level is that level which has 50% probability of finding an electron at any temperature.

in n type semiconductor , fermi energy band lies nearer to the conduction band .

in p type semiconductor, fermi energy band lies nearer to valence band .

Explanation:

• NOTE : for an intrinsic semiconductor , the fermi energy level is right at the centre between the valence band and conduction band as the probability of finding electrons in conduction band is equal to the probability of finding holes in valence band

•   for n type semiconductor , the number of electrons are greater than the number of electrons . Thus the probability of finding electrons in conduction band is greater . Therefore ,  the fermi level is close to the conduction band .

• However for p type semiconductor , holes are majority carriers  and thus the fermi energy level is closer to valence band .