Leakage current reduction in pentacene-based thin film transistor using asymmetric source/drain electrodes

In this work, we propose the concept of achieving a lower off-current in organic thin film transistors (OTFTs) by asymmetric source/drain with low and high work-function metals. The artificial hole barrier height (h-BH) at the drain-channel junction formed by this method prevents hole carriers transport from source to drain through the pentacene layer during the off-state. On-current is not affected by this artificially formed h-BH because the effective h-BH is reduced in the on-state. As a result, in the asymmetric Ni-Ti and Ni-Al OTFTs, the off-currents are decreased by 12 and 18.3 times, respectively, compared to that in the symmetric S/D device.