Controlled n-type doping of a molecular organic semiconductor: Naphthalenetetracarboxylic dianhydride (NTCDA) doped with bis(ethylenedithio)-tetrathiafulvalene (BEDT-TTF)

We present a study of controlled n-type doping in molecular organic semicon ductors: Naphthalenetetracarboxylic dianhydride is doped by cosublimation w ith the donor molecule bis(ethylenedithio)-tetrathiafulvalene. Electrical p arameters are deduced from temperature-dependent measurements of the conduc tivity and the thermopower for various dopant concentrations. The results a re compared to the predictions of a standard model commonly used for crysta lline semiconductors. The Fermi level shifts towards the transport level, t he conductivity is increased, and the mobility decreases with the doping ra tio. (C) 2000 American Institute of Physics. [S0021-8979(00)00607-1].