Charge Transport in Imperfect Organic Field Effect Transistors: Effects of Charge Traps

Tamika A. Madison, Adam G. Gagorik, Geoffrey R. Hutchison. “Charge Transport in Imperfect Organic Field Effect Transistors: Effects of Charge Traps.” J. Phys. Chem. C 2012 116(22) pp11852-11858. Available Online. The Supplemental information is available as a pdf download here: Madison SI

Monte Carlo simulations were used to study the effects of charge traps on charge transport in monolayer organic field effect transistors. The results show that the source drain current decreases as the trap/barrier concentration increases, reaches a minimum, and increases as the concentration reaches 100%, regardless of the trap/barrier distribution. More current is predicted for heterogeneous trap distributions than for homogeneous trap distributions due to wider conduction pathways that allow for more charge carriers to reach the drain electrode. Also, the distributions of distances and potential energy between charge carriers and trap sites were shown to depend on the heterogeneity of the traps and device geometry and, in many cases, are non-Gaussian in shape. We also found exponential tails for some ranges of heterogeneity. These results suggest that more experimental work is needed to gain more insight into the energetic density of states in electronic devices made from mixed films of organic semiconductors.