A percolative approach to transport and excess noise in polyacene semiconductors

Electrical transport measurements performed in polyacene thin films as a function of the applied voltage, pointed out the existence of a sharp peak in the relative spectral density of current noise occurring at voltages corresponding to the region of crossover between the Ohmic regime and the space charge limited current regime. Recently we have proposed an explanation of these experimental findings in terms of noise due to trapping and detrapping processes of the injected carriers by deep traps. This interpretation was carried out by adopting a phenomenological model making use of the measured current-voltage characteristics. To check this interpretation we have developed a new percolation model which will be discussed here.