This study investigates the effect of different types of SiO2 on the electronic and surface properties of pentacene films. Developing better contacts on dielectrics is one of the main challenges for pentacene-based transistor technology. The water contact angle variation indicates more hydrophobic thermally grown SiO2 surfaces than sol-gel SiO2 surfaces, suggesting that the thermally grown SiO2 dielectric enables a better molecular arrangement as the pentacene layer is deposited. It is found that the carrier mobility in pentacene on thermally grown SiO2 dielectrics is higher than that in pentacene on sol-gel SiO2 dielectrics. The Hall-effect analysis by using the polaron theory revealed that the enhanced carrier mobility is due to the increased spacing between molecules. (C) 2013 Elsevier B.V. All rights reserved.