This problem concerns a specimen of gallium arsenide, GaAs, which has 2 x 1017 cm-3 donors and an unknown number of acceptors. A measurement is made on the specimen and it is found that it is p-type with an equilibrium hole concentration, po, of 5 x 1017 cm-3. At room temperature in GaAs, the intrinsic carrier concentration, ni, is 107 cm-3, the hole mobility, μh is 300 cm2/Ns, and the electron mobility, μe is 4000 cm2/Ns. The minority carrier lifetime, t is 10-9 s.

(a) What is the net acceptor concentration, NA (= Na-Nd), in the sample, and what is the total acceptor concentration, Na?

(b) What is the equilibrium electron concentration, no, in this sample at room temperature?