Nanoscale Surface Morphology and Rectifying Behavior of a Bulk Single‐Crystal Organic Semiconductor

Local surface measurements of rubrene single crystals reveal interesting insights on carrier transport mechanisms at the active interface of high-performance field-effect “air-gap stamp” transistors. Scanning tunnelling microscopy (STM) images, combined with atomic force microscopy and X-ray diffraction, reveal directly the position and orientation of individual molecules in the a–b plane (see figure and inside cover). Local current–voltage curves recorded using STM in the dark and under light indicate a rectifying p-type behavior.