Field-effect modulated Seebeck coefficient measurements in an organic polymer using a microfabricated on-chip architecture

D Venkateshvaran,D Emin,J Moriarty,H Sirringhaus,A J Kronemeijer

doi:10.1063/1.4867224

D Venkateshvaran, D Emin + Show 3 more

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https://doi.org/10.1063/1.4867224

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Abstract

We developed an on-chip microfabricated architecture for high-accuracy gate voltage modulated Seebeck coefficient measurements on an organic field-effect transistor (FET). The microfabricated device comprises integrated heaters and temperature sensors that enable simultaneous Seebeck and FET measurements on devices with practical channel lengths on the order of 50 μm. We exemplify the capabilities of this architecture by investigating the transition from conduction in the semiconductor bulk to conduction in the accumulation layer of a conjugated polymer FET.

Highlights

Charge carrier transport in organic field-effect transistors (FETs) is usually addressed by measuring the temperature and gate voltage dependence of the field-effect mobility.[1,2] The Seebeck coefficient is another key transport coefficient, which governs the efficiency of thermoelectric converters, and provides unique, complementary insight into the electronic structure of functional materials
If a temperature differential T is applied across a conducting solid, charges within the solid diffuse from the hot to the cold end and an electric field builds up within the system to oppose any further diffusion of charges
The heat transported with a charge carrier is governed by its exchange of energy with atomic vibrations

Summary

Introduction

Charge carrier transport in organic field-effect transistors (FETs) is usually addressed by measuring the temperature and gate voltage dependence of the field-effect mobility.[1,2] The Seebeck coefficient is another key transport coefficient, which governs the efficiency of thermoelectric converters, and provides unique, complementary insight into the electronic structure of functional materials. A more powerful experimental configuration is to perform Seebeck measurements on an FET, which allows investigation of the Seebeck coefficient as a function of carrier concentration by varying the applied gate voltage.

Results

Conclusion