energy band gap

  1. what is meant by semiconductor ?

Ans.) It is a substance whose properties lie in between conductor and insulators i.e at high temperatures it act as conductor and at low temperature it acts as insulator .the conductivity range of this substance lies in between 10-6 to 104 (W-m) .example :

2. what is meant by conductors ?Ans.) conductors are the substance which allows electricity through them ex :-silver,copper etc

3.)what is meant by insulators ?Ans.) insulators are the substance which does not allow current to flow through it ex :diamond,graphite .

4.) What is the difference in between insulators and conductors ?

Ans.) The main difference in between insulators and conductors arises in terms of electrical behavior .the reason for the difference in  electrical behavior of conductors and insulators are due to the difference between their electronic structures .  in conductors free electrons are more and in insulators all electrons are tightly packed . 

5.) what is band gap and its units?
Ans.)  it is defined as the distanc between the valence band of electrons and the conduction band .its units are "volts"

6.) what is ghe importance of band gap ?Ans.) band gap is the important concept to understand many phenomena associated with the nanomaterials .whenever there is an overlap of valence and conduction bands ,the electron can move across freely into the conduction nand as happens in the case of conductors  .

                                             or



The energy difference between the highest occupied energy state of the valence band and the lowest unoccupied state of the conduction bandis called the band gap 


7.) what is meant by energy gap ?

Ans.) In semiconductors and insulators, electrons are fixed to the no.of bands ofenergy, and forbidden from other regions. The term "band gap" refers to the energy difference between the top of the valence band and the bottom of the conduction band. 

8.) what is meant by valence bond
9.)what is meant by conduction band 

10.) what are the energy band gap values of  si and ge ?

Ans.) the energy band gap values for si and ge are 1.14,ev 0.67ev 

11.) what is meant by intrinsic semiconductor ? 

Ans.) These are defined as the pure form of semiconductors or semiconductor with undoped ex: galium

12.) what is meant by extrinsic semiconductor ? 

Ans.) these are the impure form of semiconductors (or) semiconductors after doping ex: phosphorus ,arsenic














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