Fundamental Benefits of the Staggered Geometry for Organic Field-Effect Transistors

In this letter, decisive advantages of the staggered-type organic field-effect transistors (OFETs) over the coplanar type are elucidated by 2-D device simulation. It is found that the charge transport in the channel is not limited by the contact electrode in staggered OFETs, whereas coplanar OFETs show strongly contact-limited behavior. This dissimilarity originates from the continuity (staggered) or discontinuity (coplanar) of the carrier concentration at the channel ends, which is directly connected to the channel potential profile. The calculated current-voltage curves also support these arguments as the current in coplanar OFETs follows the contact-limited transistor model.