# Homework Help: How to identify if a semiconductor is n-type or p-type?

1. May 12, 2014

### rwooduk

please see attached image for problem

if a dopant gives an electron it's an n-type, if a dopant takes an electron it's a p-type.

i cant see how to relate the hall coefficient value to the property of being a n-type or p-type semiconductor?

any pointers on this would really be appreciated, thanks

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2. May 12, 2014

### Staff: Mentor

Electrons flowing in one direction will get deflected in the same direction as holes flowing in the opposite direction - for one doping type you get negative electrons at one side, for the other doping type you get positive holes at this side. This leads to a different hall coefficient.

3. May 12, 2014

### Jufro

The Hall Coefficient is:
RH = $\frac{1}{nq}$​
For electrons, q= -e, and our hall coefficient is:
RH = $\frac{-1}{ne}$​
Therefore we know that n-type semiconductors have negative RH.

4. May 13, 2014

### rwooduk

hm so simple, many thanks!