How come "holes" in semiconductors are considered positive in charge ?

Abhishek
Member • Dec 30, 2012

How come "holes" in semiconductors are considered positive in charge ?

As we know semiconductor is bipolar, means containing two charge carrying particles. One electron & other holes, electron is negatively charged while holes are positive charged.
My question is why "holes" are considered as positive charged particles ?
Is it based on plain assumption or any theory is related behind this concept ?
Throw me some light 😒

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Kaustubh Katdare

Administrator • Dec 30, 2012

Hmm, because the 'positive' or 'negative' charge is relative. In simplest words: Absence of light is 'darkness'. Did I make sense? 😨

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[Prototype]

Member • Dec 30, 2012

Hole is nothing but vacancy of electron. Hence when any electron find a hole near it, i will try to fill that vaccancy. In other words, this holes are attracting electrons to come and sit over them. Since electrons are negatively charges and as we know, opposite charges attracts each other, holes are said to be positively charged.

A simple example would be suppose you are travelling in a bus which is full of passengers and you are travelling standing in the bus. Now as soon as some sitting passenger gets up, the near by person grabs his seat reducing the number of standing passenger.

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Scorpion007

Member • Dec 30, 2012

In semiconductor Holes are generate by doping technique. We add Two type of impurities in semiconductor i.e trivalent (atom which have 3 free electron) and pentavalent(the atom which have five free electron). semiconductor like Si have only 4 free electrons . when we combine trivalent impurity to Si then its three free electron combine with three Silicon's free electrons but one electron remain free .that deficiency of electrons is called hole. electrons have -ve charge so holes is form due to deficiency of electron and assume as +ve charged. if u wana more detail let me know

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lal

Member • Dec 30, 2012

Holes are said to be positive because, if a hole is present in an atom it imparts a '+e' charge to it. We cant say hole has a positive charge, but sure if it is present, then the atom becomes positive. In that case, saying hole is positively charged can be justified.

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Abhishek Rawal

Member • Dec 31, 2012

Thank you for answering but sorry to say that I was just checking on you guys whether we,EC CEans know basic electrons & holes concept or not . Sorry friends. :disappointed:

I will try to explain the concept - why holes are positive charge.
So, first of all - Holes are positively charged but this concept is not an "assumption".Holes are not assigned +e charge just because other charge i.e electrons are -e.

Now back to point,by using theory of "hall-effect" you can determine whether the unknown semiconductor is p type or n type.According to this theory,current I flowing is in positive X direction & transverse magnetic field in positive B direction, hence force exerted on it will be in negative Y direction.

The current flowing i.e. in semiconductor maybe due to holes moving left to right (or holes right to left).Hence whether carriers are electrons or holes, they will be forced to set down in the semiconductor.

If semiconductor is n-type material, so it have majority carriers as electrons, these electrons will accumulate downward & this portion will become negatively charged respect to top of semiconductor material.
Now in p-type semiconductor material, it is found that at downward direction holes are gathered & at upward electrons (minority), so when practically finding potential between down side of semiconductor & up side - it was found that down-side is heavily positive, hence "holes" are considered classical free positive charge.

PS : Please don't feel offended, it was just a way to share knowledge 😀

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Kaustubh Katdare

Administrator • Dec 31, 2012

The_Big_K
In simplest words: Absence of light is 'darkness'. Did I make sense? 😨
=

Troll_So_Hard
Holes are not assigned +e charge just because other charge i.e electrons are -e.
Isn't that what I meant? 😨

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Abhishek Rawal

Member • Dec 31, 2012

The_Big_K
Isn't that what I meant? 😨
Being honest, I didn't understood what you was trying to say so unfortunately i have to ignore it 😛
please elaborate a more ☕

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Ramani Aswath

Member • Dec 31, 2012

A 'Hole' being essentially electrons (negative charge) having been removed, it has a net positive charge.

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Scorpion007

Member • Jan 1, 2013

Troll_So_Hard
Being honest, I didn't understood what you was trying to say so unfortunately i have to ignore it 😛
please elaborate a more ☕
Practically No holes type of thing is exist. Unbounded Space Or deficiency of Electrons is known as holes

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Abhishek Rawal

Member • Jan 1, 2013

Scorpion007
Practically No holes type of thing is exist. Unbounded Space Or deficiency of Electrons is known as holes
Take out a book of "Integrated Electronics" by Sir Jacob Millman second edition (Yeah! the one who gave us Millman theorem), refer to page number 29 & 31, there is an entirely well explained "hall-effect theory", which proves that holes are not an "imaginary" thing, it is free positive charge carrier.
☕

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Scorpion007

Member • Jan 1, 2013

Troll_So_Hard
Take out a book of "Integrated Electronics" by Sir Jacob Millman second edition (Yeah! the one who gave us Millman theorem), refer to page number 29 & 31, there is an entirely well explained "hall-effect theory", which proves that holes are not an "imaginary" thing, it is free positive charge carrier.
☕
Who said sir holes are imaginary thing. Holes are real.Hole is a vacancy of electron .it is a conceptual opposite of electron.Hole is different from positron. Vacancy cannot moves . practically electrons jumps from one hole to another hole so that at the same time it fill a hole and create a hole while leaving its previous position.for example assume we have 10 empty chairs in series. Now one person sit on first chair ,then move towards second chair and so on. as he move next vacancy seems to move backward. . See this link below may be it help.
<a href="https://en.wikipedia.org/wiki/Electron_hole" target="_blank" rel="nofollow noopener noreferrer">Electron Hole</a>

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Abhishek Rawal

Member • Jan 1, 2013

I said that because you said "practically no hole type thing exist".
Refer to the theory i mentioned,I am saying the same thing you are saying with taking a theory into consideration.
'nuff said.

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Jeffrey Arulraj

Member • Jan 2, 2013

I want you guys to ponder on this Hole is absence of electrons and so it is an abstract one (imaginary one). But how come mobility of it be less when compared to that of electron. They have same magnitude of charge then Why does the retarding force is higher in hole movements ?

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Scorpion007

Member • Jan 2, 2013

Troll_So_Hard
I said that because you said "practically no hole type thing exist".
Refer to the theory i mentioned,I am saying the same thing you are saying with taking a theory into consideration.
'nuff said.
I think, I misunderstood u sorry .

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Abhishek Rawal

Member • Jan 2, 2013

Scorpion007
I think, I misunderstood u sorry .
No need to be sorry,buddy.
We are simply debating which is good 😀

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dayamayee

Member • Jan 7, 2013

actually,hole does not exist...when the electron displaces,that place becomes vacant..we call the vacancy as hole..
for example,if u sit in a chair and your sir says to get up..then you will get up...
if u r not there in chair,if your sir sees the empty chair and tells to get up,what is the use?who will get up?
similarly,electron can move and can get excited...hole is an imaginary charge...absence of light is darkness..similarly,the opposite charge of negative is positive..so we assign positive charge to hole..

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