The diffusion length for electrons L_n = 3.16| mu in an n-doped (N_d = 10^17 cm^-3) semiconductor is known at a temperature T = 300K. The recombination lifetimes are also tau_p = tau_n = 1.0 ns. Find the conductivity of the semiconductor. Solution conductivity = Ln * Nd/T = 1.05 * 1000 = 1050 m-ohm-1 conduction time = 1.2 sec.