Diffusive capacitance in space charge limited organic diodes: Analysis of peak in capacitance-voltage characteristics

摘要

One of the significant features of capacitance-voltage (C-V) characteristics of organic diodes is the occurrence of a peak near the built-in voltage due to competition between diffusion and drift of carriers. The voltage dependence of the rise in small signal capacitance prior to the peak is modulated by the transit time of the carriers and leads to a linear 1/C~(2/3) vs V dependence, which has been demonstrated both through simulation, and experiments using small molecule (m-MTDATA) based diodes. The utility of such analysis in obtaining threshold voltages significant for characterization of organic diodes has been demonstrated.