Equilibrium trap-controlled carrier mobility in systems of randomly fluctuating localized states

ABSTRACT Equilibrium trap-controlled carrier transport is examined in materials with randomly fluctuating energies of localized states. It is shown that, at a given temperature, temporal fluctuations described by the 1/f noise set an upper limit Ed for the activation energy Ea of carrier release from localized states. The value Ed decreases with decreasing temperature. Under these conditions, firstly the activation energy of the equilibrium mobility decreases at low temperatures, simulating a transition from the trap-controlled to the hopping mode of carrier transport, and secondly an equilibrium transport regime occurs in materials with long (exponential or even power-law) tails of localized states.