A striking performance improvement of fullerene n-channel field-effect transistors via synergistic interfacial modifications

For fullerene based n-channel transistors, remarkably improved device characteristics were achieved via charge injection and transport interfacial synergistic modifications using low-cost aluminium source/drain electrodes. Compared with the reference device without any modifications (device A), the as-fabricated transistor ( device H) showed a dramatic improvement of saturation mobility from 0.0026 to 0.3078 cm(2) V-1 s(-1) with a maximum on-off current ratio of 106 and a minimum subthreshold slope of 1.52 V decade(-1). AFM and XRD analysis manifested that the deposited C-60 films on PVA/OTS successive-modified SiO2 substrate were highly dense polycrystalline and uniform with larger crystalline grain and less grain boundary. A gap state assisted electron injection mechanism was proposed to explicate the enhanced electrical conductivity considering BCP modification for charge injection interface, which has been well corroborated by a diode-based injection experiment and a theoretical calculation of contact resistances. We further demonstrated the application of the concept modification method to enable comparative time-stable operation of fullerene n-channel transistors. Given many key merits, we believed that this general method using multi-interface modifications could be extended to fabricate other n-channel OFETs with superior electrical performance and stability.