Hole transport in self-organized oligosilane thin films with highly ordered hopping sites

Self-organized oligosilane thin films possess molecular orientation normal to substrates with multilayered structure. This unique order of or-conjugated molecules results in good hole transport properties. In the present work, carrier transport properties at low temperature are studied for 1,10-diethyldecamethylsilane polycrystalline films. Even at a temperature as low as 173 K, a time-of-flight transient photocurrent waveform showed a clear plateau and a sharp decay, whose shape is similar to that at room temperature. Their hole mobility followed Arrhenius type temperature dependence with a small activation energy of 0.09 eV. The hole mobility of 6.3 x 10(-5) cm(2)/Vs at 193 K was more than 2 orders of magnitude higher than that of typical polysilanes, which inevitably contain disordered structures hindering smooth carrier transport.