Single domain transport measurements of C60 films

TL;DR

This study investigates the growth and electrical properties of potassium-doped C60 thin films on silicon, revealing how substrate termination affects film morphology and conductivity, with implications for organic semiconductor applications.

Contribution

It provides detailed analysis of how substrate termination influences C60 film growth mode and electrical properties, including resistivity and superconducting fluctuations.

Findings

Substrate termination drastically affects C60 film growth mode.

Resistivities of films are comparable to bulk single crystals.

Excess conductivity above superconducting transition linked to 2D fluctuations.

Abstract

Thin films of potassium doped C60, an organic semiconductor, have been grown on silicon. The films were grown in ultra-high vacuum by thermal evaporation of C60 onto oxide-terminated silicon as well as reconstructed Si(111). The substrate termination had a drastic influence on the C60 growth mode which is directly reflected in the electrical properties of the films. Measured on the single domain length scale, these films revealed resistivities comparable to bulk single crystals. In situ electrical transport properties were correlated to the morphology of the film determined by scanning tunneling microscopy. The observed excess conductivity above the superconducting transition can be attributed to two-dimensional fluctuations.