//Ex2_9 Pg-91
clc

disp("For P-type,Nd=0. By charge neutrality and mass action law,")

disp("      p + Nd = p = +na = (ni)^2/n")

disp("or    n^2 + Na*n - (ni)^2 = 0")

disp("Solving the quadratic equation for n and discharging the extraneous negative root,one obtains")

disp("      n = 0.5*(-Na + sqrt(Na^2 + 4*ni^2))")

disp("Knowing n,one obtains from mass action law p = ni^2/n")

disp("For N-type doping,Na=0. By analogous procedure,")

disp("      p = 0.5*(-Nd +sqrt(Nd^2 + 4*Ni^2));  n=ni^2/p")