watch setup video
How to distinguish p-type conductivity from n-type conductivity?
The calculated Hall coefficient is positive for p-type conductivity and negative for n-type conductivity.
How to determine the direction of magnetic field between two magnets?
Magnetic field is directed from the North pole of a magnet to the South pole of another magnet. A compass needle (marked blue at North end) will point to the South pole of a magnet. Then, another end of this magnet is the North pole.
How contacts to your samples are made? Are they Ohmic?
The contracts to GaN and Si samples are made by soldering pure Indium at samples corners. They are nearly Ohmic, what can be checked by passing electric current in different directions.
Can I determine the conductivity type of a semi-insulating semiconductor with this setup?
It is a difficult task, not because of simplicity of the setup but mostly because Ohmic contacts are very difficult to make for semi-insulating semiconductor samples. You will also need an external direct current source with higher voltage applied and a very sensitive voltmeter.
Can I change magnetic field in this setup?
No. The magnetic field (about 0.9 T) is fixed and it is optimal for the proposed experiment.