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Velocity of electrons in different Energy bands

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Y.SAI SARASWATHI

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Hello,
Why the mobility of electrons is higher than that of mobility of holes?
Hole is nothing but absence of electrons then why is it so?
I found in the Google that it is because mobility of holes is mobility of electrons in valence band
Why electrons can move freely in conduction band than that of in valence band/
Band is nothing but energy level representation,there is no physical significance for it wright.
 

udayan92 said:
This should give a good explanation.
https://www.edaboard.com/threads/43840/
Click to expand...
Thank you that link is useful,but i have one more doubt,
Conduction band is nothing but electrons having higher energy and they can easily overcome nuclear attraction I know that in case of crystalline materials energy levels group together and form bands but that also links with the properties of atom)
Consider a example that sufficient energy is externally applied to remove an electron from conduction band(let me know if it is not possible)then also a hole forms wright,then they will have equal mobility at that time.
 

If you want a simple mental picture of why electrons are
faster than holes, consider this. A conduction-band electron
is a guy in an empty ballroom. He can move freely, other
than dodging a table or two. A valence-band hole, is an
empty space in a crowded ballroom. For that space to move,
dancer after dancer has to get out of its way. That's a
slow process. Unless you're carrying an axe dripping blood,
or something. But we don't concern ourselves with "psycho
holes" other than in reliability (hot carrier).
 
I presume you are referring to free electrons. Really make sense that a hole moving ( what implies on an electron pushing it ) takes energy from the "system" what is irradiated, even in negligible levels, but enough to decay its speed, I think.
 

dick_freebird said:
If you want a simple mental picture of why electrons are
faster than holes, consider this. A conduction-band electron
is a guy in an empty ballroom. He can move freely, other
than dodging a table or two. A valence-band hole, is an
empty space in a crowded ballroom. For that space to move,
dancer after dancer has to get out of its way. That's a
slow process. Unless you're carrying an axe dripping blood,
or something. But we don't concern ourselves with "psycho
holes" other than in reliability (hot carrier).
Click to expand...
Thank you
I want to know whether that force that makes the electron move is nuclear attraction or not(give me explanation in quantum physics terms)
In your example as one cannot move in a crowded ballroom freely ,holes cannot move freely(i,e reverse moment of electrons) is due to those strongly packed electrons due to nuclear attraction or not ?
 

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