Differentiate between extrinsic and intrinsic semiconductor, Chemistry

Assignment Help:

Differentiate between extrinsic and intrinsic semiconductor. Obtain an expression for the carrier concentration for an intrinsic semi-conductor. Also demonstrate that Fermi level in an intrinsic semiconductor lies approximately half way between the top of valence band and the bottom of conduction band.

In intrinsic semiconductors, conduction is because of intrinsic processes characteristics of crystal, without influence of impurities. A pure crystal of silicon or germanium is an intrinsic semiconductor. Electrons which are excited from the top of the valence band to the bottom of the conduction band by thermal energy are responsible for conduction. Number of electrons excited across the gap can be calculated from the Fermi-Dirac probability distribution. In extrinsic semiconductors, conduction is because of the presence of extraneous impurities.  Process of deliberate addition of controlled quantities of impurities to a pure semiconductor is known as doping. Addition of impurities markedly increases the conductivity of a semiconductor. Conductivity  of  an  intrinsic semiconductor  depends  on  concentration  of  charge  carriers,  ne and  nh.  Mobility  of conduction electrons  and  holes  µe and  µh can  be  defined  as  drift  velocity  acquired  by them  under  unit  field  gradient.  The conductivity σ of a semiconductor can be written

 

220_semiconductor.png

1780_semiconductor.png


Related Discussions:- Differentiate between extrinsic and intrinsic semiconductor

Determine the calories, The Calorie, used to express food heat values, is s...

The Calorie, used to express food heat values, is similar as a kilocalorie of heat energy . If you eat a chocolate bar from the United States with 600 Calories of food energy, how

Calculate the mole fraction of nh3, What will happen if you mix nitrogen an...

What will happen if you mix nitrogen and hydrogen gas at room temperature? Explain your reasoning. Calculate the mole fraction of NH 3 that would form theoretically at 298.15

Amongst the following covalent bonding, Amongst the following covalent bond...

Amongst the following covalent bonding is found in: (1) Sodium chloride (2) Magnesium chloride (3) Water (4) Brass Ans:  Water

What is anionic intermediate, What is anionic intermediate The spectrum...

What is anionic intermediate The spectrum is consistent with the formation of an anionic intermediate-a stable Meisenheimer complex.  (The dotted lines symbolize resonance delo

Photochemistry, How to prepare my seminar paper ?

How to prepare my seminar paper ?

Reaction involving cleavage of with removal of h as proton, Reaction involv...

Reaction involving cleavage of with removal of 'H' as proton Alcohols are stronger acids as compared to terminal acetylene but are not acidic enough to react along with aqueous

Acidity, A sample of water collected in the field had a pH of 6.8. By the ...

A sample of water collected in the field had a pH of 6.8. By the time it was analyzed in the lab, the pH had decreased to 6.0. Give a possible explanation.

Partition coefficient, what is the effect on the distribution of solute if ...

what is the effect on the distribution of solute if the solvents have mutual miscibility

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd