Browsing by Author "Melaku, Seid"

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    Effects of Concentration and Localization Length on Charge Carrier Mobility in Organic Disordered Semiconductors
    (Addis Ababa University, 2018-08-04) Melaku, Seid; Demeyu, Lemi (PhD)
    Using computer simulations, we show that the dependence of the hopping carrier mobility on the electric field _(F) in a disordered organic semiconducting polymer of random energy sites described by a Gaussian density of states is determined by the localization length _ and not by the concentration of sites N. This result is in drastic contrast to what is usually assumed in the literature for a theoretical description of experimental data and for device modeling, where N􀀀1=3 is considered as the decisive length scale for _(F). In the proposed it is assumed that the localized states are randomly distributed in energy and space coordinates. The expression for hopping conductivity is obtained for the Gaussian density of states and the analysis of electric field dependent hopping mobility is shown by the Poole-Frenkel behavior is only valid in medium electric field.