Effect of Defects Buried in Pentacene/Alkanethiol Self-Assembled Monolayer/Au Film on Its Electronic Properties Visualized by Scanning Tunneling Microscopy/Spectroscopy

We have used scanning tunneling microscopy/spectroscopy to visualize the spatial correlation between buried structural defects and observed electronic properties in organic device structures. As a typical structure of an organic field-effect transistor, we have prepared pentacene/alkanethiol self-assembled monolayer (SAM)/Au samples with or without defects associated with a gap state at the molecule/Au interface. The effect of the defects, which were hidden behind the pentacene overlayers, on the electronic properties of the SAM was clearly observed. The method used in this study has potential for evaluating the nanoscale correlation between electrical properties and hidden defects inside organic devices. (C) 2010 The Japan Society of Applied Physics