I am working on a practice exam for semiconductor physics. Can anyone help me figure out how to determine whether we have donor or acceptor impurity in Gallium Arsenide?
Gallium is column 3 and (I think) it has a valence of 3. Arsenide is column 5 and (I think) it has a valence of 5. But it has a valence of 4 when it is GaAs?
Based on the information I believe I will be provided in the exam proper, I will know only the periodic group and/or atomic number, and/or valence.
I am given these choices as impurities:
Si <-- Donor impurity --> n-type semiconductor S <-- Donor impurity --> n-type semiconductor P <-- ?? Zn <-- Acceptor impurity --> p-type semiconductor
So you can see I have the answers, I just don't know how to get there.