Carbon-Passivated Ni Electrodes for Charge Injection in Organic Semiconductors

Ferromagnetic electrodes covered with ultrathin carbon films are fabricated by chemical vapor deposition and rapid thermal annealing (RTA) to grow graphene and amorphous carbon on prepatterned Ni electrodes for testing their capacity to inject charges into a p-type polymer semiconductor. Chemical and composition analysis confirms that the carbon film strongly reduces the surface oxidation of the Ni. The electrical performances measured in three-terminal devices integrating such electrodes as source and drain provide insight into the quality of the interface between ferromagnetic contact and organic semiconductor. RTA-processed electrodes exhibit the lowest interface resistance for hole injection into organic transistor devices, on par with benchmark gold electrodes. These results indicate that this approach presents an attractive strategy for the fabrication of solution-processed organic devices of potential applicability for spintronics.