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All of the distributed electron states in the conduction band is represented by an effective density of states (NC)
Prâthâmēsh Hâtkâr
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Is bismuth a semiconductor or conductor?
the band structure of bismath suggests a low density of conduction electrones and holes,so it is semi conductor
Why is a rubber band an insulator?
The electron configuration of rubber (natural of artificial is such that there is a big gap between valance band and conduction band of electrons. Electrons has to make a transition from valence band to conduction band in order to conduct electricity.
How does a conductor and insulator work?
CONDUCTORThe distance between conduction band and valence band is very small therefore an electron can easily jump to conduction band by overcoming weak nuclear forces. Hence, electric current can easily flow through it.INSULATORThe distance between conduction band and valence band is very large therefore an electron cannot jump to conduction band by overcoming weak nuclear forces. Hence, electric current cannot flow through it.
Why fermi energy level is midway between conduction band and valence band in semiconductors?
To be exact EF should be at the valence band edge (EV) at 0K because no energy state above EV are occupied at 0K; however, for intrinsic semiconductors there are no states in the band gap anyway, so placing the EF anywhere in the band gap including conduction band edge does not add any states as being occupied. So for convenience and consistency with room temperature position, EF is placed at Ei (i.e. room temperature intrinsic Fermi level position).
Why does the electrical conductivity of pure metal decrease with temperature while that of semiconductors increases?
The conductivity depends on the passage of charged particles especially electrons. In metals electrons are easily available in conduction band and so its conductivity is high. As we increase the temperature then core of atoms vibrate largely. So with positive charge it could easily minimize the electrons in the conduction band and hence fall in conductivity In case of semiconductor there will be usually forbidden gap between valence band and conduction band. So conduction is poor at ordinary temperature. But as we increase temperature that would allow electrons to reach conduction band as covalent bonds get broken. Hence higher conductivity
Is bismuth a semiconductor or conductor?
the band structure of bismath suggests a low density of conduction electrones and holes,so it is semi conductor
Are free electron in valence band or conduction band?
In semiconductors free electrons are in conduction bands.
Possibility of holes in conduction band?
hoes are vacancies left by the electron in the valence band. hence there cannot be holes in the conduction band
What are conduction band?
The quantum mechanical energy band where electrons reside in semiconductors that participate in electrical conduction.
Why conduction band and valence band partially filled?
No. Conduction band is basically the unfilled energy levels into which electrons can be excited to provide conductivity.
What is the gap between valance band and conduction band in a semi conductor?
Conduction band - The unfilled energy levels into which electrons can be excited to provide conductivity.Valence band - The energy levels filled by electrons in their lowest energy states.
Can extrinsic semiconductor conduct at 0 k?
Normally, no electron energy states exist in the band gap, the gap between the valence band and conduction band in a semiconductor. However, if we dope the semiconductor, i.e. add donor (n type) or acceptor (p type) atoms to it, we introduce new electron energy states in the band gap! Take for example silicon, in which we introduce phosphorus, which is a group V element and thus a donor atom. This will introduce extra filled electron states just below the conduction band. Now, this all happens at 0K, so no current can flow (this is logical as electrons don't move at this temperature, even with an electric field applied). But if we raise the temperature e.g. until room temperature at 300K, the electrons gain energy and can jump into the free energy states in the conduction band. These electrons in the conduction band can now conduct electricity.
What is the difference between direct and indirect energy?
The band gap represents the minimum energy difference between the top of the valence band and the bottom of the conduction band, However, the top of the valence band and the bottom of the conduction band are not generally at the same value of the electron momentum. In a direct band gap semiconductor, the top of the valence band and the bottom of the conduction band occur at the same value of momentum.In an indirect band gap semiconductor, the maximum energy of the valence band occurs at a different value of momentum to the minimum in the conduction band energy
What are the difference between direct and indirect band gap materials?
In a direct band gap the electron only needs energy to jump to the conduction band. In an indirect band an electron needs energy and momentum to jump to the conduction band
What are conduction?
The quantum mechanical energy band where electrons reside in semiconductors that participate in electrical conduction.
Why is a rubber band an insulator?
The electron configuration of rubber (natural of artificial is such that there is a big gap between valance band and conduction band of electrons. Electrons has to make a transition from valence band to conduction band in order to conduct electricity.
How does a conductor and insulator work?
CONDUCTORThe distance between conduction band and valence band is very small therefore an electron can easily jump to conduction band by overcoming weak nuclear forces. Hence, electric current can easily flow through it.INSULATORThe distance between conduction band and valence band is very large therefore an electron cannot jump to conduction band by overcoming weak nuclear forces. Hence, electric current cannot flow through it.
