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It's a lot of confusion!, seriously! lot of-! The holes, the charge carriers in p-type semiconductors. Right? But what if all the holes, all of them travels to the negative terminal? What about the charge carriers then? Holes can't move further! Temperature isn't that high to generate new holes! So, what about the so called HOLE CURRENT in p-type semiconductors?

Can someone please clear all these doubts?

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If you have a semiconductor you need so-called ohmic (non-blocking) contacts so that you can apply a voltage and induce a current. These are typically formed by highly doped semiconductor regions close to the contacts which make the usually existing Schottky barriers so thin that electrons can tunnel through these barriers. When, in a p-type semiconductor, holes reach the negative metal contact they recombine with the electrons provided (by tunneling) from the metal of the contact. That means they disappear and the conduction current continues as an electron current in the metal. Remember that holes are just missing electrons in the valence band of the semiconductor. When these holes in the valence band (which is otherwise completely filled with electrons) encounter electrons (a process called recombination) they disappear. On the other hand, at the positive contact, holes are generated at the contact because electrons from the valence band tunnel into the metal leaving holes behind. These holes travel under the influence of the applied electric field to the negative contact producing the hole current.

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