Ok thanks so concentration of electrons(n) is the number of electrons per unit volume and the concentration of holes(p) is the number of holes per unit volume. What I don't get is how would you find these quantities, are they specific to the type of material for e.g. in this case it is silicon...
Heres the question:
A sample of pure silicon, which has four valence electrons is doped with gallium, which has three valence electrons, to give a concentration of 10^23 m^-3.
a. Is the material n-type or p-type?
b. If the electron mobility is 0.14 m^2/Vs and the hole mobility is 0.05...