Performance of Organic Field Effect Transistors with Self-Improved Cu/Organic Interfaces

We fabricate pentacene-based organic field effect transistors (OFETs) with Cu as source and drain (S-D) electrodes. The fabricated devices stored for ten hours under ambient atmospheric conditions exhibit superior performance compared with the as-prepared devices. The field-effect mobility increases from 0.012 to 0.03cm²V^-1s^-1, and the threshold voltage downshifts from -14 to -9V. The on/off current ratios are close to the order of 10⁴. The improved performance of the stored devices is attributed to the formation of thin Cu oxide at the Cu electrodes/organic interfaces. These results suggest a simple and available way to optimize device properties and to reduce fabrication cost for OFETs.