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Hello Prakash,
In PN junction theory the holes never move, only the electrons moves and only because of that current flows after the recombination of electrons and holes.
And for your 1st question refer R.S.Sedha.
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hi prakash,
valence electrons are nothing but the electrons of the outer shell of any atom....when you give a sufficient amount of energy to the atom then the electrons of the last shell or valence electrons knock out from the atom leaving behind the ion having valency equal to the removed electrons,in electronics we refer such electrons "FREE ELECTRONS"..
now your second question:
in PN junction theory these free electrons plays a very important role,when an electron is ejected from an atom then a vacancy is created in the atom,this vacancy is generally called holes in electronics terms...now there are so many free electrons in a semiconductor material so they occupy this vacancy thus the creation of another hole in the material,,in this way a hole hypothetically moves in a semiconductor material....
a hole is nothing but a vacancy left after an ejection of an electron...
i hope this will help you
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Thanks dude,,,,,,,,,,,,,,
it s right```````
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With out moving holes how will creade the -ve immobile ion
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k dude .. u said holes are not moved.. do u know abt the hole current .. how it happens?...
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@prakash:as stated by chetan,holes are created as a result of vacancy.So in real,when electrons move from one vacancy to another,it looks like the holes are moving on the other side(like theory of relativity,you got to fix your reference 😛 ).This is the hole current.It has same direction as conventional current(that is,opposite to flow of electrons) 😀
Hope that helps,if not ping me
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@prakash hope you will be satisfy by the answer of cranky,he appropriately answered your question,,
if you have still any doubt,then imagine a row of eight seats in which eight students are seated,now suppose the student at the eighth position stands up and goes somewhere,leaving behind a vacant seat,now a student who was seated at the fourth position stands up and takes eigth position thus leaving behind a vacant seat..now visualise it, we had a vacant seat at the eigth position initially and after some timeit was at the fourth position an so on...
same phenomenon happens with the electrons and holes...
now consider students as electrons and vacant seats as holes,you will see that actually holes do not move,it is the electron which moves leaving behind a vacancy(holes),which hypothetically moves opposite to the direction of electron,(in real this is the direction of positive charge,thats why holes are consider as a positive charge).
if you want to UNDERSTAND this problem clearly then please refer the book DONALD SCHILLING....
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ok pa, i like it ,
share some more thoughts 2 me
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Holes never move! I mean, how can they? they are created when electrons move. We just "say" that holes move in a direction because we consider the conventional current to be opposite of the flow of electrons. Its always electrons that move in a current.
Hole current is just a way to express the conventional current. And when an area gets depleted of electrons. ie when electrons move from one part to other, there is a deficiency of electrons at one side which has only holes remaining. SO we call it positively charged as the negative charge has reduced!
PS: @ Prakash: Dude, please use proper English language (written). Don't use SMS language. It is one of the rules of the forum. And if there are any more doubts, they are welcome 😀
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