[somebodyy]

In p-type semiconductor the charge carriers are said to be positive, that is electron hole. But still isn't the electrons are movoing ? If positives move to the right that means that in reality electrons are moving to the left. Then how is it that the hall effect experiment for p-type semiconductors and n-type semiconductor are opposite of each other? Please I need as simple explanation as possible?

[Corribus]

Holes are "pseudoparticles".  They are not real particles but they offer some conceptual assistance when dealing with systems such as conductors and semiconductors which feature "bands" that are "seas of electrons".

Actually, wikipedia has a nice description of their usefulness.

http://en.wikipedia.org/wiki/Electron_hole

In the case of a p-type semiconductor, rather than talking about a whole mess of electrons moving one way, it is sometimes simpler to speak of a single whole moving the opposite way, simply as a means of modelling what is going on.  The effect is identical.  The bus analogy at Wikipedia is a good one to help visualize this.

[somebodyy]

Holes are "pseudoparticles".  They are not real particles but they offer some conceptual assistance when dealing with systems such as conductors and semiconductors which feature "bands" that are "seas of electrons".

Actually, wikipedia has a nice description of their usefulness.

http://en.wikipedia.org/wiki/Electron_hole

In the case of a p-type semiconductor, rather than talking about a whole mess of electrons moving one way, it is sometimes simpler to speak of a single whole moving the opposite way, simply as a means of modelling what is going on.  The effect is identical.  The bus analogy at Wikipedia is a good one to help visualize this.

But the effect is not identical. hall test of p-type is reverse of the one for n-type as if in p-types the moving charge is really positive. check out the link below. there's an explanation there but too complex for me to undrstand.

http://physics.stackexchange.com/questions/10800/how-can-the-hall-effect-ever-show-positive-charge-carriers

[Enthalpy]

You're absolutely right.

Simply a lack of electron in a nearly full band would still behave as an electron, for the direction of the Hall voltage.
You're a lucky man. When I asked my microelectronics teachers they couldn't answer that.

The reason is that electrons at the top of the valence band have a negative mass. They behave abnormally. This is completely due to the overwhelming influence of the crystal lattice. At the top of the valence band, the curvature of E versus k (or p) is negative, corresponding to a negative mass.

It makes the introduction of holes much more meaningful and useful, because then, these lacks of electrons have a positive mass. They behave like normal particles in vacuum, as opposed to what valence electrons do. Including in the Hall effect.

By the way, holes are not limited to semiconductors. About half of all metals conduct mainly by holes - and the mass of their charge carriers differs from the electron in vacuum. Hall experiments at school are made with silver just because electrons happen to have their vacuum mass in silver. Any semiconductor would have made the experiment way easier, but then students would ask silly questions.

[somebodyy]

Hi Enthalpy, thanks for answering. I hare read similar answer in wikipedia. But still it is very complex. Why do we even have to get into waves, isn't there particle explanation to this? Do I really have to kill myself by undestanding those strange things. What does negative mass mean anyways ? This is so stupid. I'm not telling these to you, I just yell out my ideas to the world. I hate quantum mechanics and what it does to the science....   

[somebodyy]

Simply bypassing the question by bringing the idea that under some conditions the mass of electron is negative is so idiotic. That idea itself brings thousands of other silly question like:  if the mass of electron is negative, then that means nucleous repels electron instead of attracting it. then electron can't even be there, it would fly away from that nucleous and from lattice. outside the material electron would experience gravitational force which would repel it into space bla bla bla....

[somebodyy]

I'm not saying to you Enthalpy, don't misunderstand me. You too must have read that answer somewhere.

[Borek]

I hate quantum mechanics and what it does to the science....   

You sound like if it was something forced upon science for no reason. Thing is, we have not selected the world to behave this way - it did long before we started trying to understand it. And as Feynman put it long ago - it is nature that is always right, not us.

[somebodyy]

I think Einstein was right, and the reason we have quantum mechanics out there is because there are some pieces missing from the picture of science and quantum mechanics is lazy scientist's way to solve things. Quantum mechanics is a temporary solution and it will be gone someday. So sad that Einstein didn't have enough lifetime to solve this problem.

So is there a more particle like explanation to this? why hall effect is different for p-types ?

Are there any common materials for which hall effect is negative or I have no way but to buy a p-type silicon wafer online? I have to see it for myself.

[Enthalpy]

The negative Hall voltage is strictly a consequence of electrons being waves.

QM is the proper explanation to our world, no alternative is in sight, all others fail. So make peace with it and learn it, it's fascinating.

By Einstein, you mean reject the random nature of particles and hope for hidden variables? This has been proven false and even impossible, experimentally. Old Albert was wrong on this point. Forget it.

Electrons can have a negative or positive mass in solids, and this mass differs numerically from the one in vacuum. Not only Hall measures tell it. All semiconductor components that process light (LED, laser diodes, detectors, germanium lenses...) rely on this "effective mass", sometimes in a very subtle manner. Semicon engineers use it to make predictions that are verified at the components. Every single DVD burner is a proof of it.

You write "nuclei would repel an electron with negative mass" but an electron with an effective mass pertains to a band, hence is already delocalized over many nuclei. Which nucleus should repel the electron toward what nucleus-free direction? It seems that you'd like to imagine electrons as point-like particles, and this misconception leads you directly into wrong deductions.

You can look for positive "hall coefficients" in metals:
http://www.ifsc.usp.br/~lavfis/BancoApostilasImagens/ApEfHall-CondEletr/EfHallMetals-5_3_03.pdf
http://www.phys.utk.edu/labs/modphys/Hall%20Effect.pdf page 8
for instance iron, zinc, cobalt, molybdenum... have a positive coefficient resulting from the negative mass.

Hall experiments are usually made with semiconductors to have fewer charge carriers, which are then faster for a given current and give a higher Hall voltage. If using a metal, whose carrier density is huge, a thin foil improves the situation; the Hall voltage stays small and difficult to observe. I suggest to cable everything, then place or remove a permanent magnet and try to observe a voltage variation - a few microvolts with thin foils.