The emission rates for electrons and holes are given, respectively by
= ^nvthnNc exp I _ Еашкт Et
= ^pvthpN„exp(_ Et kEVbm J (8)
where <3n, Nc, and vthn are the thermal capture cross section, the density of states, and the thermal velocity of holes, respectively. av, Nv, and vthp are the same parameters for holes. ECbm, EVbm, and Et are the energy levels of the conduction band minimum, the valence band maximum, and the trap, respectively.