Dielectric substrate effect on the temperature-dependent electrical properties of pentacene films

Developing better contacts on dielectrics is one of the main challenges for pentacene-based transistor technology. This study investigates the effect of inorganic dielectrics on the temperature-dependent electronic property of pentacene films. It is found that the carrier mobility in the pentacene film deposited on a SiN_x dielectric is higher than that in the pentacene film deposited on a SiO₂ dielectric. However, the carrier density does not change substantially. The dependence of the carrier mobility upon temperature indicates the dominance of tunneling (hopping) at low (high) temperatures. The Hall-effect analysis by using the polaron theory revealed that the enhanced carrier mobility is due to the modified spacing between molecules in the pentacene layer.