Compensation occurs when a semiconductor is doped with both donor and acceptor dopants. Using the fact that n0p0=ni^2 (mass action law) and p0+Nd=n0+Na (charge neutrality assuming all dopants are ionized), answer the following:
a) derive an expression for n0=n0(ni,Nd,Na)
b)for Nd-Na > 0, under what condition is the relation n0=Nd-Na a good approximation?
c) Under what condition is p0=Na-Nd a good approximation?
d) why should charge neutrality be a constraint?