Electronic and surface properties of pentacene films deposited on SiO2 prepared by the sol–gel and thermally grown methods

• The carrier mobility of pentacene on thermally grown and sol–gel SiO2 was researched.
• The enhanced carrier mobility of pentacene on thermally grown SiO2 was observed.
• The dominance of tunneling (hopping) at low (high) temperatures was observed.
• The carrier mobility is correlated with the morphology of pentacene films.

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.