Investigation into the modelling of field-effect carrier mobility in disordered organic semiconductors

[[abstract]]Organic semiconductors have attracted significant interest because of their potential application in electronic devices. One of the most important parameters in such an application is the carrier mobility, which is low when compared with inorganic semiconductors. In the past, significant effort has been spent to produce high mobility organic semiconductors, even though the best room temperature value reported is only a few cm(2)/V.s. In the work, the field-effect carrier mobility in organic semiconductors is examined by correlating reported data for pentacene with simulations based on the correlated disorder model. Using the rms width of the density of states (DOS) as the main variable, a good match between data and simulations has been produced. The results suggested that the carrier mobihty in disordered organic semiconductors could be solely dependent on sigma, the rms width of the DOS. The rather small value of sigma used in the calculations pointed to the need for a better understanding into the transport mechanism within this regime. Other fitting parameters affected the carrier mobility included the site spacing and the barrier height, both of which were capable of changing the carrier mobility. A more careful examination revealed that there were physical constraints limiting the values of these parameters.[[note]]SC