Contact effect in organic thin film transistors

The contact effect on the performances of organic thin film transistors (OTFTs) is studied here. We fabricate Bottom-gated top-contact Pentacene-OTFTs on heavily doped n type Silicon wafers with using Al modified by MoO 3 as source and drain electrodes. Field effect mobility μ ef of the OTFT reaches 0.42cm 2 /V ·s,the threshold voltage and the on/off current ratio arrive at -5.0 V and 4.7×10 3 respectively. The electric potential distribution in the channel is qualitively investigated by means of middle probe method (MPM) and the output curve is simulated by the charge drift method. Considering the contact effect,the μ ef is greatly improved to 1.1 cm 2 /V ·s,which indicates the importance of the contact engineering in OTFTs.