Steady-state space-charge-limited current analysis of mobility with negative electric field dependence

摘要

We revisit the theory of steady-state space-charge-limited current (SS-SCLC) enhanced by Frenkel emission originally addressed by Murgatroyd using analytical rather than numerical integration to obtain an exact solution. For the first time, the analysis is also extended to the case of mobility exhibiting negative field dependence, generally observed in disordered materials at lower electric field. For the case of positive electric field dependence, we confirm that Murgatroyd's original solution is close to the exact solution for low and moderately high electric fields. At a very high field, the exact solution is consistent with the analytical solution given by Barbe. For the case of negative electric field dependence, the fit expression retains the same functional form as Murgatroyd's solution, however with a different exponential factor of -0.801. The development of SS-SCLC theory for the case of negative field dependence is an important step in the generalization of this analysis technique to the investigation of complex materials such as disordered organic semiconductors. Published by AIP Publishing.