Onset of electroluminescence from bilayer light emitting diodes under space charge limited majority carrier injection

An analytic theory has been developed to analyze the rise of electroluminescence from bilayer light emitting diodes upon applying a rectangular voltage pulse if the current of majority carriers is space charge limited while minority carrier injection is electrode limited. The onset of electroluminescence is governed by the growth of the interfacial charge densities rather than by the transit time. This result suggests that, for appropriate interfacial energy barriers, balanced injection can be established even if only one of the electrodes is ohmic. A qualitative agreement between theory and experiment has been obtained.