Potentiometric Parameterization of Dinaphtho[2,3-b:2 ',3 '-f]thieno[3,2-b]thiophene Field-Effect Transistors with a Varying Degree of Nonidealities

Abstract

Organic transistors with different structures are investigated to address the applicability and reliability of parameter extraction. A dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene channel is coupled with pristine or functionalized gold bottom and top contacts to reveal a geometrical impact on the device performance and nonidealities. Scanning Kelvin probe microscopy is employed as a key method to quantify the channel and contact potential in operation. Taking full account of the contact effects and including an explicit threshold voltage in calculation are shown to be critical to access the intrinsic carrier mobility, while simple derivative-based extraction may over- or underestimate it. Further analytical developments correlate individual physical parameters, leading to the discovery that pentafluorobenzenethiol self-assembled on gold predominantly affects the carrier mobility rather than the injection barrier.