Organic thin film transistors (OTFT) have gained considerable interest due to their potential applications, and the related device models have been developed in recent years. Now standard drift-diffusion equations implemented in Minimos-NT are being extended for organic transistors. Due to the low conductivity of organic materials, some quantities in the drift-diffusion equations are being newly defined. An equivalent doping model used in silicon and the traps model used in amorphous systems will be incorporated into drift-diffusion equations. An effective density of states in organic materials has been defined which is somewhat different from a single equivalent level used by some authors.
A mobility model based on variable range hopping (VRH) is being extended to be field-dependent for both two-dimensional and three-dimensional space. A connection between the percolation theory and the effective mobility model for accumulation code TFT will be built afterwards based on this result. Further work will focus on the simulation of organic transistors and organic light-emitting diodes using the new drift-diffusion simulator.