For three P-N junction diode samples A, B, and C, acceptor and donor carrier concentrations are the same 10^15/cm^3 and 10^18 /cm^3, respectively. Band gaps for the three samples A, B, and C are 0.8 eV, 1.5 eV, and 1.8 eV, while the electron and hole effective masses of density of states are the same in all the three materials, me = 0.1mo and mh = 0.5mo, where is the electron mass in free space.
(A) Find the built-in potentials for these three devices at T = 300 K. Comment on the comparison of estimated built-in potentials.